query: type of antigen that triggers an allergic reaction

pos: Type I hypersensitivity the entire body is involved, then anaphylaxis can take place, which is an acute, systemic reaction that can prove fatal. Some examples: Type I hypersensitivity Type I hypersensitivity (or immediate hypersensitivity) is an allergic reaction provoked by reexposure to a specific type of antigen referred to as an allergen. Type I is not to be confused with type II, type III, or type IV hypersensitivities, nor is it to be confused with Type I Diabetes or Type I of any other disease or reaction. Exposure may be by ingestion, inhalation, injection, or direct contact. In type 1 hypersensitivity, B-cells are

pos: Type I hypersensitivity Type I hypersensitivity Type I hypersensitivity (or immediate hypersensitivity) is an allergic reaction provoked by reexposure to a specific type of antigen referred to as an allergen. Type I is not to be confused with type II, type III, or type IV hypersensitivities, nor is it to be confused with Type I Diabetes or Type I of any other disease or reaction. Exposure may be by ingestion, inhalation, injection, or direct contact. In type 1 hypersensitivity, B-cells are stimulated (by CD4+TH2 cells) to produce IgE antibodies specific to an antigen. The difference between a normal infectious immune response and a

pos: Type I hypersensitivity the entire body is involved, then anaphylaxis can take place, which is an acute, systemic reaction that can prove fatal. Some examples: Type I hypersensitivity Type I hypersensitivity (or immediate hypersensitivity) is an allergic reaction provoked by reexposure to a specific type of antigen referred to as an allergen. Type I is not to be confused with type II, type III, or type IV hypersensitivities, nor is it to be confused with Type I Diabetes or Type I of any other disease or reaction. Exposure may be by ingestion, inhalation, injection, or direct contact. In type 1 hypersensitivity, B-cells are

pos: Patch test approximately 85–90 percent of contact allergic eczema, and include chemicals present in metals ("e.g.", nickel), rubber, leather, formaldehyde, lanolin, fragrance, toiletries, hair dyes, medicine, pharmaceutical items, food, drink, preservative, and other additives. A patch test relies on the principle of a type IV hypersensitivity reaction. The first step in becoming allergic is sensitization. When skin is exposed to an allergen, the antigen-presenting cells (APCs) – also known as Langerhans cell or Dermal Dendritic Cell – phagocytize the substance, break it down to smaller components and present them on their surface bound major histocompatibility complex type two (MHC-II) molecules. The APC

pos: Prostaglandin DP1 receptor inflammation and blocks antigen-presenting langerhans cell function in mice. This results suggest that DP1 can promote or suppress allergic responses depending on the animal model tested and, perhaps, the type of allergic reaction investigated. Allergen inhalation challenge of humans produces rises in the PGD2 levels in their Bronchoalveolar lavage fluids. Furthermore, the administration of PGD2 into the nose or skin of human volunteers produces local symptoms of allergy and the inhallation of PGD2 into asthmatics causes constriction of the airways as well as the potentiation of airway constriction responses. These reactions, similar to those produced in animal studies, may be

pos: Robert Cooke (physician) or antigen slowly neutralized those antibodies responsible for the allergic reaction. Robert Cooke (physician) Robert Anderson Cooke (1880–1960) was an American immunologist and allergist. In 1916 Cooke and Albert Vandeveer demonstrated the role of heredity in the origins of allergy. According to Cooke, 48% of his allergic patients had allergies in their family history. While the trait of allergy is transmitted through heredity, parents and children may be allergic to different substances. In 1918, Dr. Cooke suggested a mechanism of action for allergen injections as a "desensitization or hyposensitization," analogous to tolerance achieved in experimental anaphylaxis induced in animals. This

pos: Atopy Atopy Atopy is a predisposition toward developing certain allergic hypersensitivity reactions. Atopy may have a hereditary component, although contact with the allergen or irritant must occur before the hypersensitivity reaction can develop. Maternal psychological trauma in utero may also be a strong indicator for development of atopy. The term "atopy" was coined by Coca and Cooke in 1923. Many physicians and scientists use the term "atopy" for any IgE-mediated reaction (even those that are appropriate and proportional to the antigen), but many pediatricians reserve the word "atopy" for a genetically mediated predisposition to an excessive IgE reaction. The term is

pos: Allergic inflammation immediate allergic reaction or as a Type I allergic reaction. The reaction is caused by the release of histamine and mast cell granule proteins by a process called degranulation, as well as the production of leukotrienes, prostaglandins and cytokines, by mast cells following the cross-linking of allergen specific IgE molecules bound to mast cell FcεRI receptors. These mediators affect nerve cells causing itching, smooth muscle cells causing contraction (leading to the airway narrowing seen in allergic asthma), goblet cells causing mucus production, and endothelial cells causing vasodilatation and edema. The late phase of a Type 1 reaction (which develops 8–12

pos: H1 antagonist H1 antagonist H antagonists, also called H blockers, are a class of medications that block the action of histamine at the H receptor, helping to relieve allergic reactions. Agents where the main therapeutic effect is mediated by negative modulation of histamine receptors are termed antihistamines; other agents may have antihistaminergic action but are not true antihistamines. In common use, the term "antihistamine" refers only to H-antihistamines. Virtually all H-antihistamines function as inverse agonists at the histamine H-receptor, as opposed to neutral antagonists, as was previously believed. In type I hypersensitivity allergic reactions, an allergen (a type of antigen) interacts with

pos: Antibody FcR it binds. The ability of an antibody to bind to its corresponding FcR is further modulated by the structure of the glycan(s) present at conserved sites within its Fc region. The ability of antibodies to bind to FcRs helps to direct the appropriate immune response for each different type of foreign object they encounter. For example, IgE is responsible for an allergic response consisting of mast cell degranulation and histamine release. IgE's Fab paratope binds to allergic antigen, for example house dust mite particles, while its Fc region binds to Fc receptor ε. The allergen-IgE-FcRε interaction mediates allergic signal

pos: Systemic lupus erythematosus proteins (autoimmunity). During an immune reaction to a foreign stimulus, such as bacteria, virus, or allergen, immune cells that would normally be deactivated due to their affinity for self-tissues can be abnormally activated by signaling sequences of antigen-presenting cells. Thus triggers may include viruses, bacteria, allergens (IgE and other hypersensitivity), and can be aggravated by environmental stimulants such as ultraviolet light and certain drug reactions. These stimuli begin a reaction that leads to destruction of other cells in the body and exposure of their DNA, histones, and other proteins, particularly parts of the cell nucleus. The body's sensitized B-lymphocyte cells

pos: MELISA metal sensitivity in metal-sensitive patients. A MELISA test measures a so-called type-IV delayed hypersensitivity reaction. In contrast to a type-I allergy, which is mediated by IgE antibodies and is often tested using an ELISA test, a type-IV hypersensitivity reaction is mediated by T-lymphocytes (or memory lymphocytes) that have had prior contact with a given allergen. In genetically predisposed individuals, an ongoing everyday exposure to allergens can induce the type-IV hypersensitivity with a resulting allergic reaction. The test procedure is a cell culture and requires live memory lymphocytes. Lymphocytes are isolated and cultured in an incubator for five days. A portion

pos: Allergen Allergen An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies. In technical terms, an allergen is an antigen that is capable of stimulating a type-I hypersensitivity reaction in atopic individuals through Immunoglobulin E (IgE) responses. Most humans mount significant Immunoglobulin E responses only as a defense against parasitic infections. However, some individuals may respond to many common environmental antigens. This hereditary predisposition is called atopy. In atopic individuals, non-parasitic antigens stimulate inappropriate

pos: Patch test (hives) or anaphylaxis (such as peanuts) cause a type I hypersensitivity reaction whereby the part of the food molecule is directly recognized by cells close to the skin, called mast cells. Mast cells have antibodies on their surface called immunoglobulin E (IgE). These act as receptors, and if they recognize the allergen, they release their contents, causing an immediate allergic reaction. Type I reactions like anaphylaxis are immediate and do not take 2 to 4 days to appear. In a study of patients with chronic hives who were patch tested, those who were found allergic and avoided all contact with

pos: Milk allergy cooking structurally degrades protein molecules, potentially making them less allergenic. Allergic responses can be divided into two phases: an acute response that occurs immediately after exposure to an allergen, which can then either subside or progress into a "late-phase reaction," prolonging the symptoms of a response and resulting in more tissue damage. In the early stages of acute allergic reaction, lymphocytes previously sensitized to a specific protein or protein fraction react by quickly producing a particular type of antibody known as secreted IgE (sIgE), which circulates in the blood and binds to IgE-specific receptors on the surface of other kinds

pos: Patch test their allergen, including dietary intake, stopped having hives. Those who started eating their allergen again had recurrence of their hives. Patch test A patch test is a method used to determine whether a specific substance causes allergic inflammation of a patient's skin. Any individual suspected of having allergic contact dermatitis or atopic dermatitis needs patch testing. Patch testing helps identify which substances may be causing a delayed-type allergic reaction in a patient, and may identify allergens not identified by blood testing or skin prick testing. It is intended to produce a local allergic reaction on a small area of the

pos: Allergic inflammation Allergic inflammation Allergic inflammation is an important pathophysiological feature of several disabilities or medical conditions including allergic asthma, atopic dermatitis, allergic rhinitis and several ocular allergic diseases. Allergic reactions may generally be divided into two components; the early phase reaction, and the late phase reaction. While the contribution to the development of symptoms from each of the phases varies greatly between diseases, both are usually present and provide us a framework for understanding allergic disease. The early phase of the allergic reaction typically occurs within minutes, or even seconds, following allergen exposure and is also commonly referred to as the

pos: Allergic conjunctivitis Horner-Trantas dots are specific features of vernal type. Giant papillary conjunctivitis is not a true ocular allergic reaction and is caused by repeated mechanical irritation of the conjunctiva. Repeated contact with the conjunctival surface caused by the use of contact lenses is associated with GPC. PKC results from a delayed hypersensitivity/inflammatory reaction to antigens expressed by various pathogens. Common agents include Staph. aureus, Mycobacterium tuberculosis, Chlamydia and Candida. A detailed history allows physicians to determine whether the presenting symptoms are due to an allergen or another source. Diagnostic tests such as conjunctival scrapings to look for eosinophils are helpful in

pos: Allergic response Allergic response An allergic response is a hypersensitive immune reaction to a substance that normally is harmless or would not cause an immune response in everyone. An allergic response may cause harmful symptoms such as itching or inflammation or tissue injury. Allergies are an abnormal immune reaction. The human immune system is designed to protect the body from potential harm and in people who have allergies the immune system will react to allergens (substances that trigger an immune response). The immune system will produce immunoglobulin E, IgE, antibodies for each allergen. The antibodies will cause cells in the body to

pos: Allergic response Allergic response An allergic response is a hypersensitive immune reaction to a substance that normally is harmless or would not cause an immune response in everyone. An allergic response may cause harmful symptoms such as itching or inflammation or tissue injury. Allergies are an abnormal immune reaction. The human immune system is designed to protect the body from potential harm and in people who have allergies the immune system will react to allergens (substances that trigger an immune response). The immune system will produce immunoglobulin E, IgE, antibodies for each allergen. The antibodies will cause cells in the body to

pos: Allergic conjunctivitis Beta chemokines such as eotaxin and MIP-1 alpha have been implicated in the priming and activation of mast cells in the ocular surface. When a particular allergen is present, sensitization takes place and prepares the system to launch an antigen specific response. TH2 differentiated T cells release cytokines, which promote the production of antigen specific immunoglobulin E (IgE). IgE then binds to IgE receptors on the surface of mast cells. Then, mast cells release histamine, which then leads to the release of cytokines, prostaglandins, and platelet-activating factor. Mast cell intermediaries cause an allergic inflammation and symptoms through the activation of

neg: Allergic transfusion reaction from a donor who has allergies, followed by antigen exposure. An allergic transfusion reaction is a type of transfusion reaction that is defined according to the Center for Disease Control (CDC) as: An allergic transfusion reaction is diagnosed if two or more of the following occur within 4 hours of cessation of transfusion: A probable diagnosis results if any one of the following occurring within 4 hours of cessation of transfusion: Treatment of an allergic transfusion reaction is to immediate stop the transfusion. If the only symptoms are mild (i.e., hives and itching), the patient may be treated with an

neg: Allergic contact dermatitis primes and sensitizes the immune system for an allergic response, and an "elicitation phase", in which this response is triggered. As it involves a cell-mediated allergic response, ACD is termed a Type IV delayed hypersensitivity reaction, making it an exception in the usage of the designation "allergic," which otherwise usually refers to type I hypersensitivity reactions. Contact allergens are essentially soluble haptens (low in molecular weight) and, as such, have the physico-chemical properties that allow them to cross the stratum corneum of the skin. They can only cause their response as part of a complete antigen, involving their association with

neg: Prausnitz–Küstner test person when the antibodies mix with the antigen. This demonstrates a type I hypersensitivity reaction, and the allergic reaction to the injected antigen is confirmed for the patient being tested. A positive PK test usually appears as a wheal and flare. The test was developed by Otto Prausnitz and Heinz Küstner. The first PK test occurred in 1921 when Prausnitz injected Küstner's serum into his abdominal skin. Küstner had previously noted that he developed allergic symptoms after eating fish. After eating some fish, Prausnitz's skin became hot, red, and swollen at the site of the serum injection, confirming their hypothesis

neg: Stomatitis IV (delayed) hypersensitivity reaction that occurs in susceptible atopic individuals when allergens penetrate the skin or mucosa. Allergens, which may be different for different individuals, combine with epithelial-derived proteins, forming haptens which bind with Langerhans cells in the mucosa, which in turn present the antigen on their surface to T lymphocytes, sensitizing them to that antigen and causing them to produce many specific clones. The second time that specific antigen is encountered, an inflammatory reaction is triggered at the site of exposure. Allergic contact stomatitis is less common than allergic contact dermatitis because the mouth is coated in saliva, which

neg: Immune system that damages the body's own tissues. They are divided into four classes (Type I – IV) based on the mechanisms involved and the time course of the hypersensitive reaction. Type I hypersensitivity is an immediate or anaphylactic reaction, often associated with allergy. Symptoms can range from mild discomfort to death. Type I hypersensitivity is mediated by IgE, which triggers degranulation of mast cells and basophils when cross-linked by antigen. Type II hypersensitivity occurs when antibodies bind to antigens on the patient's own cells, marking them for destruction. This is also called antibody-dependent (or cytotoxic) hypersensitivity, and is mediated by IgG

neg: Prausnitz–Küstner test presence of immediate hypersensitivity in humans; test serum from an atopic individual is injected intradermally into a normal subject; the normal subject is challenged 24–48 hours later with the antigen suspected of causing the immediate hypersensitivity reaction in the atopic individual. Serum, suspected to contain IgE antibodies, is drawn from the allergic (atopic) patient. This serum is injected intradermally into a non-allergic person. The suspected antigens are then intradermally injected into the non-allergic person 24–48 hours later. If the person being tested for an allergy has made antibodies for the antigen, this will cause a local reaction in the non-allergic

neg: Anaphylaxis the last exposure to the agent in question, the lower the risk. Anaphylaxis is a severe allergic reaction of rapid onset affecting many body systems. It is due to the release of inflammatory mediators and cytokines from mast cells and basophils, typically due to an immunologic reaction but sometimes non-immunologic mechanism. In the immunologic mechanism, immunoglobulin E (IgE) binds to the antigen (the foreign material that provokes the allergic reaction). Antigen-bound IgE then activates FcεRI receptors on mast cells and basophils. This leads to the release of inflammatory mediators such as histamine. These mediators subsequently increase the contraction of bronchial

neg: Drug allergy Drug allergy A drug allergy is an allergy to a drug, most commonly a medication, and is a form of adverse drug reaction. Medical attention should be sought immediately if an allergic reaction is suspected. An allergic reaction will not occur on the first exposure to a substance. The first exposure allows the body to create antibodies and memory lymphocyte cells for the antigen. However, drugs often contain many different substances, including dyes, which could cause allergic reactions. This can cause an allergic reaction on the first administration of a drug. For example, a person who developed an allergy to

neg: Drug allergy cause reactions in themselves, but by the formation of haptens. Drug allergy A drug allergy is an allergy to a drug, most commonly a medication, and is a form of adverse drug reaction. Medical attention should be sought immediately if an allergic reaction is suspected. An allergic reaction will not occur on the first exposure to a substance. The first exposure allows the body to create antibodies and memory lymphocyte cells for the antigen. However, drugs often contain many different substances, including dyes, which could cause allergic reactions. This can cause an allergic reaction on the first administration of a

neg: Prausnitz–Küstner test that Küstner was allergic to fish. A reversed Prausnitz–Küstner test involves injecting antibodies into the skin of a person who already has the antigen. A wheal and flare in the skin also demonstrates a positive reverse PK test. Prausnitz–Küstner test The Prausnitz–Küstner test (PK test, Prausnitz-Küstner reaction) is an immunologic test formerly used by physicians to determine if a patient has an allergic reaction to a specific antigen. The test has been replaced by the safer skin prick test. The PK test involves transferring serum from the test subject to another healthy person, essentially using the second person as a

neg: Allergic response itchiness, swelling, running nose, watery eyes, coughing, wheezing, trouble breathing, hives, rashes, mucus production, or a more severe reaction anaphylaxis. Allergic responses and the severity vary from person to person. Many substances can trigger an allergic reaction. Common triggers of a reaction include foods, likes nuts, eggs, milk, gluten, fruit and vegetables; insect bites from bees or wasps (often a severe response occurs); environmental factors such as pollen, dust, mold, plants like grass or trees, animal dander; medications or chemicals. Some people experience an allergic response to cold or hot temperatures outside, jewelry or sunlight. There are daily treatments to

neg: Calciphylaxis type reaction. In other words, calciphylaxis is not a hypersensitivity reaction (i.e., allergic reaction) leading to sudden local calcification. Clearly, additional factors are involved in calciphylaxis. It is also known as calcific uremic arteriolopathy; however, the disease is not limited to patients with kidney failure. The current belief is that in end-stage kidney disease, abnormal calcium and phosphate homeostasis result in the deposition of calcium in the vessels, also known as metastatic calcification. Once the calcium has been deposited, a thrombotic event occurs within the lumen of these vessels, resulting in tissue infarction. It is unknown what the triggers are

neg: Latex allergy trigger a reaction. People with latex allergies may also have or develop allergic reactions to some fruits, such as bananas. Natural rubber latex is known to cause allergic reactions of Type I (e.g. anaphylaxis) and Type IV (e.g. allergic contact dermatitis) as well as non-allergic irritant contact dermatitis. The most serious and rare form of latex allergy, Type I hypersensitivity can cause an immediate and potentially life-threatening reaction, not unlike the severe reaction some people have to bee stings. Such reactions account for a significant proportion of perioperative anaphylactic reaction, especially in children with myelomeningocele. Type I natural rubber latex

neg: Farmer's lung arise due to one's inability to recognize the cause of symptoms. Farmer's lung occurs because repeated exposure to antigens, found in the mold spores of hay, crops, and animal feed, triggers an allergic reaction within the farmer's immune system. The defense mechanisms of the body present as cold and flu-like symptoms that occur in individuals who experience either acute or chronic reactions. The mold spores are inhaled and provoke the creation of IgE antibodies that circulate in the bloodstream, these types of immune response are most often initiated by exposure to thermophilic actinomycetes (most commonly "Saccharopolyspora rectivirgula"), which generate IgG-type

neg: Delayed hemolytic transfusion reaction Delayed hemolytic transfusion reaction A delayed hemolytic transfusion reaction (DHTR) is a type of transfusion reaction. According to the Centers for Disease Control's (CDC) National Healthcare Safety Network's (NHSN) Hemovigilance Module, it is defined as: DEFINITIVE DIAGNOSIS: AND EITHER AND EITHER PROBABLE DIAGNOSIS: Delayed blood transfusion reaction occurs more frequently (1 in 20,569 blood components transfused in the USA in 2011) when compared to acute haemolytic transfusion reaction. An example of this type of reaction is if a person without a Kidd blood antigen (for example a Jka-Jkb+ patient) receives a Kidd antigen (Jka-antigen for example) in a red blood

neg: Prausnitz–Küstner test Prausnitz–Küstner test The Prausnitz–Küstner test (PK test, Prausnitz-Küstner reaction) is an immunologic test formerly used by physicians to determine if a patient has an allergic reaction to a specific antigen. The test has been replaced by the safer skin prick test. The PK test involves transferring serum from the test subject to another healthy person, essentially using the second person as a mixing vessel for antibodies and antigen. This is a pathway for transmission of blood-borne ailments like Creutzfeldt–Jakob disease, AIDS, and others, which is why the test is no longer recommended. Or in simple words, a test for the

neg: Memory B cell the essence of allergic diseases. Not all memory B cells are created in germinal centre reaction. We can also find memory B cells independent on germinal centres and memory B cells independent on T-cell help at all. These cells are differentiated from activated B cells before they enter germinal centre reaction. Their BCR has lower affinity to antigen and so the interaction with Tfh is weaker then in classical memory B cells. That is because Tfh interact with B cell via it's MHCII glycoprotein-peptide complex. The peptide comes from the antigen captured by BCR - so the weaker affinity of

neg: Lepromin with erythema (redness), or 10mm without, 48 hours post injection are positive Fernandez reactions. Unlike the tuberculin test however, another reaction occurs in lepromatous patients at the injection site 21 days post injection, also appearing as induration and possible ulceration. This late positive reaction is known as the Mitsuda reaction. These reactions differ dependent on the type of lepromin antigen used. There are two types of lepromin antigen in use that differ in the method of preparation. The Dharmendra antigen evokes a stronger early positive reaction than the Mitsuda antigen, which provokes a stronger late reaction. A strong Mitsuda reaction

neg: MCD peptide to be involved in allergic and inflammatory processes related to type I hypersensitivity reaction. MCD peptide shows neurotoxicity by inducing epileptiform seizures in rat, when intraventricularly injected. This toxicity is caused by the blockage of voltage-gated potassium channels by the MCD peptide. However, there is no toxicity of MCD administered peripherally, even at high doses. As a mast cell activator, the MCD peptide evokes large increases in antigen-specific serum immunoglobulin G (IgG) responses. Therefore, it is used as a vaccine adjuvant. MCD peptide analogs, such as [Ala12] MCD, provide a base for designing agents that can prevent IgE/Fc-RIa interactions and

neg: Antibody Ishizaka discovered IgE and showed it was a class of antibodies involved in allergic reactions. In a landmark series of experiments beginning in 1976, Susumu Tonegawa showed that genetic material can rearrange itself to form the vast array of available antibodies. The membrane-bound form of an antibody may be called a "surface immunoglobulin" (sIg) or a "membrane immunoglobulin" (mIg). It is part of the "B cell receptor" (BCR), which allows a B cell to detect when a specific antigen is present in the body and triggers B cell activation. The BCR is composed of surface-bound IgD or IgM antibodies and

neg: Skin allergy test this skin end point titration (SET) uses intradermal injection of allergens at increasing concentrations to measure allergic response. To prevent a severe allergic reaction, the test is started with a very dilute solution. After 10 minutes, the injection site is measured to look for growth of wheal, a small swelling of the skin. Two millimeters of growth in 10 minutes is considered positive. If 2 mm of growth is noted, then a second injection at a higher concentration is given to confirm the response. The end point is the concentration of antigen that causes an increase in the size of

neg: Peanut allergy h 6 are considered to be major allergens which means that they trigger an immunological response in more than 50% of the allergic population. These peanut allergens mediate an immune response via release of Immunoglobulin E (IgE) antibody as part of the allergic reaction. Some of the peanut allergens can undergo enzymatic and non-enzymatic modifications which makes them more likely to bind to ligands on antigen-presenting cells. Ara h 1 can undergo glycosylation modifications which have been shown to induce immunomodulatory responses; it stimulates lectin receptors MR and DC-SIGN on dendritic cells which further propagate cytokines and bias the immune

neg: Aeroallergen is "managed" (treated) with corticosteroids, with a 90% response rate in some studies. Various steroid sparing agents e.g. sodium cromoglycate (a stabilizer of mast cell membranes), ketotifen (an antihistamine), and montelukast (a selective, competitive leukotriene receptor antagonist) have been proposed, centering on an allergic hypothesis, with mixed results. An elimination diet may be successful if a limited number of food allergies are identified. Aeroallergen An aeroallergen ("pronounced aer·o·al·ler·gen") is any airborne substance, such as pollen or spores, which triggers an allergic reaction. Aeroallergens include the pollens of specific seasonal plants is commonly known as "hay fever", because it is most

neg: Id reaction the sides of fingers and feet as a reaction to fungal infection on the feet, athlete's foot. Stasis dermatitis, allergic contact dermatitis, acute irritant contact eczema and infective dermatitis have been documented as possible triggers, but the exact cause and mechanism is not fully understood. Several other types of id reactions exist including erythema nodosum, erythema multiforme, Sweet's syndrome and urticaria. Id reactions left untreated may become infected with bacteria. Causes include infection with dermatophytosis, "Mycobacterium", viruses, bacteria and parasites. Eczematous conditions including contact allergic dermatitis and stasis dermatitis as well as stitches and trauma have also been associated with

neg: Allergic inflammation hours and is mediated by mast cells) should not be confused with delayed hypersensitivity Type IV allergic reaction (which takes 48–72 hours to develop and is mediated by T cells). The products of the early phase reaction include chemokines and molecules that act on endothelial cells and cause them to express Intercellular adhesion molecule (such as vascular cell adhesion molecule and selectins), which together result in the recruitment and activation of leukocytes from the blood into the site of the allergic reaction. Typically, the infiltrating cells observed in allergic reactions contain a high proportion of lymphocytes, and especially, of eosinophils.

neg: Poultry allergy Poultry allergy Poultry meat allergy is a rare food allergy in humans caused by consumption of poultry meat (commonly chicken and turkey) whereby the body triggers an immune reaction and becomes overloaded with immunoglobulin E (IgE) antibodies. It can co-occur with egg allergy but more often occurs without allergy to poultry eggs. One study found that chicken and turkey meat are the primary cause of allergic reactions, whilst goose, peasant, and duck meat cause milder reaction or no symptoms. As it is a rare condition and it is not well documented; epidemiological data is unknown. Severe cases have been documented.

neg: Allergy due to the migration of other leukocytes such as neutrophils, lymphocytes, eosinophils and macrophages to the initial site. The reaction is usually seen 2–24 hours after the original reaction. Cytokines from mast cells may play a role in the persistence of long-term effects. Late-phase responses seen in asthma are slightly different from those seen in other allergic responses, although they are still caused by release of mediators from eosinophils and are still dependent on activity of T2 cells. Although allergic contact dermatitis is termed an "allergic" reaction (which usually refers to type I hypersensitivity), its pathophysiology actually involves a reaction

neg: Eosinophilic esophagitis Eosinophilic esophagitis Eosinophilic esophagitis (EoE, also spelled eosinophilic oesophagitis), also known as allergic oesophagitis, is an allergic inflammatory condition of the esophagus that involves eosinophils, a type of white blood cell. Symptoms are swallowing difficulty, food impaction, vomiting, and heartburn. Eosinophilic esophagitis was first described in children but also occurs in adults. The condition is not well understood, but food allergy may play a significant role. The treatment may consist of removal of known or suspected triggers and medication to suppress the immune response. In severe cases, it may be necessary to enlarge the esophagus with an endoscopy procedure. EoE

neg: Allergic contact dermatitis Allergic contact dermatitis Allergic contact dermatitis (ACD) is a form of contact dermatitis that is the manifestation of an allergic response caused by contact with a substance; the other type being irritant contact dermatitis (ICD). Although less common than ICD, ACD is accepted to be the most prevalent form of immunotoxicity found in humans. By its allergic nature, this form of contact dermatitis is a hypersensitive reaction that is atypical within the population. The mechanisms by which these reactions occur are complex, with many levels of fine control. Their immunology centres on the interaction of immunoregulatory cytokines and discrete subpopulations

neg: Delayed hemolytic transfusion reaction cell transfusion and forms an alloantibody (anti-Jka); upon subsequent transfusion with Jka-antigen positive red blood cells, the patient may have a delayed hemolytic transfusion reaction as their anti-Jka antibody hemolyzes the transfused Jka-antigen positive red blood cells. Other common blood groups with this reaction are Duffy, Rhesus and Kell. Delayed hemolytic transfusion reaction A delayed hemolytic transfusion reaction (DHTR) is a type of transfusion reaction. According to the Centers for Disease Control's (CDC) National Healthcare Safety Network's (NHSN) Hemovigilance Module, it is defined as: DEFINITIVE DIAGNOSIS: AND EITHER AND EITHER PROBABLE DIAGNOSIS: Delayed blood transfusion reaction occurs more frequently (1

neg: Arthus reaction Arthus reactions are characterized by severe pain, swelling, induration, edema, hemorrhage, and occasionally by necrosis. These symptoms and signs usually occur 4–12 hours after vaccination. ACIP has recommended that persons who experienced an Arthus reaction after a dose of tetanus toxoid–containing vaccine should not receive Td more frequently than every 10 years, even for tetanus prophylaxis as part of wound management. Arthus reaction In immunology, the Arthus reaction () is a type of local type III hypersensitivity reaction. Type III hypersensitivity reactions are immune complex-mediated, and involve the deposition of antigen/antibody complexes mainly in the vascular walls, serosa (pleura, pericardium,

neg: Tree nut allergy the oil, and extra roasting or processing can reduce the allergic reaction. This allergy tends to be lifelong; studies have shown that only about 9% of children outgrow their tree nut allergy. People with tree nut allergy are seldom allergic to just one type of nut, and are therefore usually advised to avoid all tree nuts, even though an individual may not be allergic to the nuts of all species of trees. Someone allergic to walnuts or pecans may not have an allergy to cashews or pistachios, because the two groups are only distantly related and do not necessarily share

neg: Type III hypersensitivity as an Arthus reaction, and is characterized by local erythema and some induration. Platelet aggregation, especially in microvasculature, can cause localized clot formation, leading to blotchy hemorrhages. This typifies the response to injection of foreign antigen sufficient to lead to the condition of serum sickness. Some clinical examples: Other examples are: Type III hypersensitivity Type III hypersensitivity occurs when there is accumulation of immune complexes (antigen-antibody complexes) that have not been adequately cleared by innate immune cells, giving rise to an inflammatory response and attraction of leukocytes. Such reactions may progress to immune complex diseases. Type III hypersensitivity occurs when

neg: Taeniasis the bloodstream and invade host tissues. This clinical condition, called cysticercosis, is the most frequent and severe disease caused by any tapeworm. It can lead to severe headaches, dizziness, occasional seizures, dementia, hypertension, lesions in the brain, blindness, tumor-like growths, and low eosinophil levels. It is the cause of major neurological problems, such as hydrocephalus, paraplegy, meningitis, convulsions, and even death. "Taenia saginata" infection is asymptomatic, but heavy infection causes weight loss, dizziness, abdominal pain, diarrhea, headaches, nausea, constipation, chronic indigestion, and loss of appetite. It can cause antigen reaction that induce allergic reaction. It is also a rare cause

neg: Arthus reaction Arthus reaction In immunology, the Arthus reaction () is a type of local type III hypersensitivity reaction. Type III hypersensitivity reactions are immune complex-mediated, and involve the deposition of antigen/antibody complexes mainly in the vascular walls, serosa (pleura, pericardium, synovium), and glomeruli. This reaction is usually encountered in experimental settings following the injection of antigens. The Arthus reaction was discovered by Nicolas Maurice Arthus in 1903. Arthus repeatedly injected horse serum subcutaneously into rabbits. After four injections, he found that there was edema and that the serum was absorbed slowly. Further injections eventually led to gangrene. The Arthus reaction involves

neg: Blood type A and antibody B. The antigens are present on the red blood cells and the antibodies in the serum. Regarding the antigen property of the blood all human beings can be classified into 4 groups, those with antigen A (group A), those with antigen B (group B), those with both antigen A and B (group AB) and those with neither antigen (group O). The antibodies present together with the antigens are found as follows: There is an agglutination reaction between similar antigen and antibody (for example, antigen A agglutinates the antibody A and antigen B agglutinates the antibody B). Thus,

neg: Allergic transfusion reaction antihistamine and if the symptoms completely disappear and the patient feels well, the transfusion may be restarted. A mild transfusion reaction during infusion usually does not progress to a more severe anaphlyactic reaction after infusion of additional product from the same unit. If the symptoms are more than mild, the transfusion should not be restarted. There is no evidence that antihistamine premedication prevents allergic transfusion reactions, although these drugs can mitigate symptoms once they occur. Allergic transfusion reaction An allergic transfusion reaction is a blood transfusion that results in allergic reaction. It is among the most common transfusion reactions to

neg: T independent antigen (TI) T independent antigen (TI) T independent antigen elicits antibody production by B lymphocytes without T lymphocyte involvement. There are 2 distinct subgroups of TI antigens, different in mechanism of activating B lymphocytes. TI-1 antigen, which has an activity that can directly activate B cells and TI-2 antigen, which has highly repetitive structure and causes simultaneous cross-linking of specific B cell receptors (BCR) on B lymphocyte. The most commonly released isotype of antibodies in this type of immune reaction is low affinity IgM. For most protein antigens, the production of antibodies by B lymphocytes is dependent on stimulation of helper T

neg: T independent antigen (TI) by dendritic cells (DC) and macrophages is required. T independent antigen (TI) T independent antigen elicits antibody production by B lymphocytes without T lymphocyte involvement. There are 2 distinct subgroups of TI antigens, different in mechanism of activating B lymphocytes. TI-1 antigen, which has an activity that can directly activate B cells and TI-2 antigen, which has highly repetitive structure and causes simultaneous cross-linking of specific B cell receptors (BCR) on B lymphocyte. The most commonly released isotype of antibodies in this type of immune reaction is low affinity IgM. For most protein antigens, the production of antibodies by B

neg: Immunopathology stronger immune response than normal. There are four different types (type one, two, three and four), all with varying types and degrees of an immune response. The problems that arise from each type vary from small allergic reactions to more serious illnesses such as tuberculosis or arthritis. The second kind of complication in the immune system is Autoimmunity, where the immune system would attack itself rather than the antigen. Inflammation is a prime example of autoimmunity, as the immune cells used are self-reactive. A few examples of autoimmune diseases are Type 1 diabetes, Addison’s disease and Celiac disease. The third

neg: Milk allergy Sometimes prednisone will be prescribed to prevent a possible late-phase type I hypersensitivity reaction. Severe allergic reactions (anaphylaxis) may require treatment with an epinephrine pen, i.e., an injection device designed to be used by a non-healthcare professional when emergency treatment is warranted. A second dose is needed in 16–35% of episodes. Most people find it necessary to strictly avoid any item containing dairy ingredients. The reason is that the individual threshold dose capable of provoking an allergic reaction can be quite small, especially in infants. An estimated 5% react to less than 30 milligrams of dairy proteins, and 1% react

neg: Antigen-antibody interaction of Anthrax; Determination of adulteration in food. It acts on antigen-antibody reaction in which the antibodies cross-link particulate antigens resulting in the visible clumping of the particle. Use: Sereologic diagnosis of Enteric Fever. In an antibody, the Fab (fragment, antigen-binding) region is formed from the amino-terminal end of both the light and heavy chains of the immunoglobulin polypeptide. This region, called the variable (V) domain, is composed of amino acid sequences that define each type of antibody and their binding affinity to an antigen. The combined sequence of variable light chain (V) and variable heavy chain (V) creates three hypervariable

neg: Loa loa filariasis immitis" as a skin test antigen for filariasis diagnosis. If the patient was infected, the extract would cause an artificial allergic reaction and associated Calabar swelling similar to that caused, in theory, by metabolic products of the worm or dead worms. Blood tests to reveal microfilaremia are useful in many, but not all cases, as one third of loiasis patients are amicrofilaremic. By contrast, eosinophilia is almost guaranteed in cases of loiasis, and blood testing for eosinophil fraction may be useful. Diethylcarbamazine has been shown as an effective prophylaxis for "Loa loa" infection. A study of Peace Corps volunteers in

neg: Scabies caused by an allergic reaction of the host's body to mite proteins, though exactly which proteins remains a topic of study. The mite proteins are also present from the gut, in mite feces, which are deposited under the skin. The allergic reaction is both of the delayed (cell-mediated) and immediate (antibody-mediated) type, and involves IgE (antibodies are presumed to mediate the very rapid symptoms on reinfection). The allergy-type symptoms (itching) continue for some days, and even several weeks, after all mites are killed. New lesions may appear for a few days after mites are eradicated. Nodular lesions from scabies may

neg: Peanut allergy Peanut allergy Peanut allergy is a type of food allergy to peanuts. It is different from tree nut allergies. Physical symptoms of allergic reaction can include itchiness, hives, swelling, eczema, sneezing, asthma, abdominal pain, drop in blood pressure, diarrhea, and cardiac arrest. Anaphylaxis may occur. It is due to a type I hypersensitivity reaction of the immune system in susceptible individuals. The allergy is recognized "as one of the most severe food allergies due to its prevalence, persistency, and potential severity of allergic reaction." Prevention may be partly achieved through early introduction of peanuts to the diets of pregnant women

neg: Antibody-drug conjugate drugs, antibody-drug conjugates target only cancer cells so that healthy cells are less severely affected. In developing antibody-drug conjugates, an anticancer drug is coupled to an antibody that specifically targets a certain tumor marker (e.g. a protein that, ideally, is only to be found in or on tumor cells). Antibodies track these proteins down in the body and attach themselves to the surface of cancer cells. The biochemical reaction between the antibody and the target protein (antigen) triggers a signal in the tumor cell, which then absorbs or internalizes the antibody together with the cytotoxin. After the ADC is internalized,

neg: Patch test Patch test A patch test is a method used to determine whether a specific substance causes allergic inflammation of a patient's skin. Any individual suspected of having allergic contact dermatitis or atopic dermatitis needs patch testing. Patch testing helps identify which substances may be causing a delayed-type allergic reaction in a patient, and may identify allergens not identified by blood testing or skin prick testing. It is intended to produce a local allergic reaction on a small area of the patient's back, where the diluted chemicals were planted. The chemicals included in the patch test kit are the offenders in

neg: Autoimmune hemolytic anemia cell. Immune hemolytic states are those, both anemic and nonanemic, which involve immune mechanisms consisting of antigen-antibody reactions. These reactions may result from unrelated antigen-antibody complexes that fix to an innocent-bystander erythrocyte, or from related antigen-antibody combinations in which the host red cell or some part of its structure is or has become antigenic. The latter type of antigen-antibody reaction may be termed "autoimmune", and hemolytic anemias so produced are autoimmune hemolytic anemias. In general, AIHA in children has a good prognosis and is self-limiting. However, if it presents within the first two years of life or in the teenage

neg: Allergic transfusion reaction Allergic transfusion reaction An allergic transfusion reaction is a blood transfusion that results in allergic reaction. It is among the most common transfusion reactions to occur. Reported rates depend on the degree of active surveillance versus passing reporting to the blood bank. Overall, they are estimated to complicate up to 3% of all transfusions. The incidence of allergic transfusion reactions is associated with the amount of plasma in the product. More than 90% of these reactions occur during transfusion. Allergic reactions from blood transfusion may occur from the presence of allergy-causing antigens within the donor's blood, or transfusion of antibodies

neg: ELISA dried onto the transparent bottom and sometimes also side wall of a well (the stationary "solid phase'/"solid substrate" here as opposed to solid microparticle/beads that can be washed away), which is usually constructed as a multiple-well plate known as the "ELISA plate". Conventionally, like other forms of immunoassays, the specificity of antigen-antibody type reaction is used because it is easy to raise an antibody specifically against an antigen in bulk as a reagent. Alternatively, if the analyte itself is an antibody, its target antigen can be used as the binding reagent. Before the development of the ELISA, the only option

neg: Allergic rhinitis type of allergic rhinitis is commonly seen in younger children. Allergic rhinitis may also be classified as Mild-Intermittent, Moderate-Severe intermittent, Mild-Persistent, and Moderate-Severe Persistent. Intermittent is when the symptoms occur <4 days per week or <4 consecutive weeks. Persistent is when symptoms occur >4 days/week and >4 consecutive weeks. The symptoms are considered mild with normal sleep, no impairment of daily activities, no impairment of work or school, and if symptoms are not troublesome. Severe symptoms result in sleep disturbance, impairment of daily activities, and impairment of school or work. Local allergic rhinitis is an allergic reaction in the nose

neg: Human anti-mouse antibody target one specific antigen. Herceptin and Avastin, two widely used cancer fighting drugs, are examples of monoclonal antibodies. For several decades, and until recently, mice were used extensively in the production of monoclonal antibodies (MAbs). But the treatments were not as effective as doctors had hoped. One problem was that patients reacted to the mouse antibodies as if they were a foreign substance, and created a new set of antibodies to the mouse antibodies. Doctors have termed this the “HAMA response,” referring to the development of Human Anti-Mouse Antibodies (HAMA). The HAMA response is essentially an allergic reaction to the

neg: Type IV hypersensitivity Type IV hypersensitivity Type 4 hypersensitivity is often called delayed type hypersensitivity as the reaction takes several days to develop. Unlike the other types, it is not antibody-mediated but rather is a type of cell-mediated response. CD4+ T1 helper T cells recognize foreign antigen in a complex with the MHC class II major histocompatibility complex on the surface of antigen-presenting cells. These can be macrophages that secrete IL-12, which stimulates the proliferation of further CD4+ T1 cells. CD4+ T cells secrete IL-2 and interferon gamma, inducing the further release of other T1 cytokines, thus mediating the immune response. Activated CD8+

neg: Precipitin Precipitin A precipitin is an antibody which can precipitate out of a solution upon antigen binding. The precipitin reaction provided the first quantitative assay for antibody. The precipitin reaction is based upon the interaction of antigen with antibody leading to the production of antigen-antibody complexes. To produce a precipitin reaction, varying amounts of soluble antigen are added to a fixed amount of serum containing antibody. As the amount of antigen added: The small, soluble immune complexes formed "in vivo" in the zone of antigen excess can cause a variety of pathological syndromes. Antibody can only precipitate antigenic substrates that are

neg: Arthus reaction the in situ formation of antigen/antibody complexes after the intradermal injection of an antigen. If the animal/patient was previously sensitized (has circulating antibody), an Arthus reaction occurs. Typical of most mechanisms of the type III hypersensitivity, Arthus manifests as local vasculitis due to deposition of IgG-based immune complexes in dermal blood vessels. Activation of complement primarily results in cleavage of soluble complement proteins forming C5a and C3a, which activate recruitment of PMNs and local mast cell degranulation (requiring the binding of the immune complex onto FcγRIII), resulting in an inflammatory response. Further aggregation of immune complex-related processes induce a local

neg: Arthralgia chili peppers, may relieve joint pain from arthritis and other conditions. Capsaicin blocks the actions of substance P, which helps transmit pain signals, and capsaicin triggers the release of pain-blocking chemicals in the body known as endorphins. Side effects of capsaicin cream include burning or stinging in the area where it is applied. Another topical option is an arthritis cream containing the ingredient, methyl salicylate (Bengay). Arthralgia Arthralgia (from Greek "arthro-", joint + "-algos", pain) literally means "joint pain"; it is a symptom of injury, infection, illnesses (in particular arthritis) or an allergic reaction to medication. According to MeSH, the

neg: Aeroallergen Aeroallergen An aeroallergen ("pronounced aer·o·al·ler·gen") is any airborne substance, such as pollen or spores, which triggers an allergic reaction. Aeroallergens include the pollens of specific seasonal plants is commonly known as "hay fever", because it is most prevalent during haying season, from late May to the end of June in the Northern Hemisphere; but it is possible to suffer from hay fever throughout the year. The pollen which causes hay fever varies from person to person and from region to region; generally speaking, the tiny, hardly visible pollens of wind-pollinated plants are the predominant cause. Pollens of insect-pollinated plants are

neg: Precipitin multivalent—that is, only antigens that have multiple antibody-binding sites epitopes. This allows for the formation of large antigen:antibody complexes. Precipitin A precipitin is an antibody which can precipitate out of a solution upon antigen binding. The precipitin reaction provided the first quantitative assay for antibody. The precipitin reaction is based upon the interaction of antigen with antibody leading to the production of antigen-antibody complexes. To produce a precipitin reaction, varying amounts of soluble antigen are added to a fixed amount of serum containing antibody. As the amount of antigen added: The small, soluble immune complexes formed "in vivo" in the

neg: Dental anesthesia medical history. Genuine allergy to LA will manifest either as Type 1 or Type 4 hypersensitivity. Signs and symptoms will vary depending on the type of allergy. Type 1 reactions have a rapid onset of symptoms which include swelling, redness, rashes, itchiness, chest tightness, breathing problems. A Type 4 reaction has a delayed onset of symptoms and is usually localized to the site of injection. If a genuine allergic reaction to LA should occur, the patient should be treated as an emergency for anaphylaxis, according to the guidelines in the respective areas. For the UK, the section on medical emergencies

neg: Colton antigen system Colton antigen system The Colton antigen system (Co) is present on the membranes of red blood cells and in the tubules of the kidney and helps determine a person's blood type. The Co antigen is found on a protein called aquaporin-1 which is responsible for water homeostasis and urine concentration. The Co antigen is important in transfusion medicine. 99.8% of people possess the Co(a) allele. Individuals with Co(b) allele or who are missing the Colton antigen are at risk for a transfusion reaction such as hemolytic anemia or alloimmunization. Antibodies against the Colton antigen may also cause hemolytic disease of

neg: Protopolybia chartergoides bugs will also eat wasps. Other creatures that eat wasps, particularly mammals, are more interested in the larvae rather than the adults. When a social wasp is in distress, it emits a pheromone that triggers nearby colony members into defensive mode, a greatly increased willingness and desire to sting. Wasps can sting repeatedly unlike their close relative, the bee. Stingers, which are actually modified egg-laying organs, are only found in females. Common symptoms of wasp stings in humans are redness, minor swelling, and itching. In the severe allergic reaction to a sting called "anaphylaxis," the body goes into shock in

neg: Charles Richet individual's sometimes lethal reaction to a second, small-dose injection of an antigen won the Nobel Prize in Physiology or Medicine. The research helped elucidate hay fever, asthma and other allergic reactions to foreign substances and explained some previously not understood cases of intoxication and sudden death. In 1914, he became a member of the Académie des Sciences. Richet discovered the analgesic drug chloralose with Richet had many interests, and he wrote books about history, sociology, philosophy, psychology, as well as theatre and poetry. He was a pioneer in aviation. He was involved in the French pacifist movement. Starting in 1902,

neg: Scarlet fever G can be given as a one time intramuscular injection as another alternative if swallowing pills is not possible. If the patient is allergic to the family of antibiotics which both penicillin and amoxicillin are a part of (beta-lactam antibiotics), a first generation cephalosporin is used. Cephalosporin antibiotics, however, can still cause adverse reactions in patients whose allergic reaction to penicillin is a Type 1 Hypersensitivity reaction. In those cases it is appropriate to choose clindamycin or erythromycin instead. Tonsillectomy, although once a reasonable treatment for recurrent streptococcal pharyngitis, is not indicated. This is due to the fact that a

neg: Elizabethan collar amount of fleas in the animal compared to animals who do not wear the collar. This is apparent mostly in cats, since those that wear the Elizabethan collar have been shown to have twice as many fleas in their coats compared to cats that have been able to groom themselves. It is also important for animal owners to make sure that the type of Elizabethan collars they use do not cause any allergic reaction to their pets, since some animals can be allergic to the plastic used in the most common clinical collars. Owners with plastic allergic pets could instead

neg: Domesticated hedgehog be allergic to items surrounding the hedgehog, such as the hedgehog's food or bedding, but it is rare that a person would be allergic to the hedgehog itself. After handling hedgehogs, some have claimed that pink dots on their hands is an allergic reaction. This is more likely caused by small pricks from the hedgehog's spines. If a hedgehog is not clean, the pricks can become infected. The infection is from contaminants on the hedgehog or on the surface of the hands, not from an allergic reaction to the hedgehog. Hedgehogs are commonly allergic to wood oils. Wood bedding should

neg: Finafloxacin disorders, including rhinitis and nasopharyngitis, have also been associated with the use of finafloxacin. People that are allergic to other quinolones may be allergic to finafloxacin as well, and use may result in an allergic reaction in that population. Adverse effects consistent with an allergic reaction to finafloxacin may include swelling of the lips, tongue, or throat, difficulty swallowing, and shortness of breath. It is not thought that an overdose of the "otic suspension" is likely to cause severe or life-threatening symptoms. Owing to the local effect of administering finafloxacin into the ears, it is unlikely that it will affect

neg: Antigen-antibody interaction Antigen-antibody interaction Antigen-antibody interaction, or antigen-antibody reaction, is a specific chemical interaction between antibodies produced by B cells of the white blood cells and antigens during immune reaction. It is the fundamental reaction in the body by which the body is protected from complex foreign molecules, such as pathogens and their chemical toxins. In the blood, the antigens are specifically and with high affinity bound by antibodies to form an antigen-antibody complex. The immune complex is then transported to cellular systems where it can be destroyed or deactivated. The first correct description of the antigen-antibody reaction was given by Richard

neg: Medical microbiology antibody to bind specifically to an antigen. The antigen (usually a protein or carbohydrate made by an infectious agent) is bound by the antibody, allowing this type of test to be used for organisms other than bacteria. This binding then sets off a chain of events that can be easily and definitively observed, depending on the test. More complex serological techniques are known as immunoassays. Using a similar basis as described above, immunoassays can detect or measure antigens from either infectious agents or the proteins generated by an infected host in response to the infection. Polymerase chain reaction (PCR) assays

neg: Benzyl benzoate loss of coordination, ataxia, convulsions, and respiratory paralysis. Benzyl benzoate can be a skin irritant when used as a topical scabicide. Overdose can result in blistering and hives or a rash can occur as an allergic reaction. As an excipient in some testosterone-replacement injectable medications, benzyl benzoate has been reported as a cause of anaphylaxis in a case in Australia. Bayer includes this report in information for health professionals and recommends that physicians "should be aware of the potential for serious allergic reactions" to preparations of this type. In Australia, reports to ADRAC, which evaluates reports of adverse drug reactions

neg: Solar urticaria believed to be a type I hypersensitivity (a mild to severe reaction to an antigen including anaphylaxis) in which an antigen, or substance provoking an immune response, is "induced by UV or visible radiation." Secondary SU can occur when a person comes into contact with chemicals such as tar, pitch, and dyes. People who use drugs such as benoxaprofen or patients with erythropoietic protoporphyria may also contract this secondary form. These items that cause this photosensitivity are exogenous photosensitizers because they are outside of the body and cause it to have a greater sensitivity to light. Also, there have been

neg: Eosinophilic esophagitis of the eosinophil type into the epithelial lining of the esophagus. This is thought to be an allergic reaction against ingested food, based on the important role eosinophils play in allergic reactions. Eosinophils are inflammatory cells that release a variety of chemical signals which inflame the surrounding esophageal tissue. This results in the signs and symptoms of pain, visible redness on endoscopy, and a natural history that may include stricturing. The diagnosis of EoE is typically made on the combination of symptoms and findings on diagnostic testing. Prior to the development of the EE Diagnostic Panel, EoE could only be

neg: Corey–Link reaction additional nucleophilic reactant, such as hydroxide or an alkoxide, then triggers an acyl substitution there to produce a carboxylic acid or ester. Various other nucleophiles can be used to generate other acyl functional groups. This sequence of steps gives a 2-azido compound, which is then reduced to the 2-amino compound in a separate reaction, typically a Staudinger reaction. The Bargellini reaction involves the same type of dichloroepoxy intermediate, formed by a different method, that reacts with a single structure containing two nucleophilic groups. It thus gives products such as morpholinones or piperazinones, alpha-amino esters or amides in which the amine

neg: Australian native bees native species of bee will cause relatively minor discomfort to most people -- "not as painful as those of a bull ant or paper wasp and last only a few minutes". However, they may sting more than once, and can cause an allergic reaction—increasing effect associated with repeated exposure to the antigen. Social species of Australian native bees do produce honey, but not much, as they are relatively primitive bee species. In cool-climate areas of Australia, all the honey the bees produce is needed by the swarm to live through winter. Collecting honey from Australian native bee nests can cause

neg: Thymic stromal lymphopoietin TSLP expression is linked to many disease states including asthma, inflammatory arthritis, atopic dermatitis, eczema, eosinophilic esophagitis and other allergic states. The factors inducing the activation of TSLP release are not clearly defined. Expression of TSLP is enhanced under asthma-like conditions (aka Airway HyperResponsiveness or AHR model in the mouse), conditioning APCs in order to orient the differentiation of T cells coming into the lungs towards a TH2 profile (T helper 2 pathway). The TH2 cells then release factors promoting an inflammatory reaction following the repeated contact with a specific antigen in the airways . TSLP-activated Langerhans cells of the

neg: Ixodes holocyclus digestive system. When the same tick attaches to the next host (e.g. a human) it transfers the alpha-gal to the tissues of that next host. The immune system of some humans recognises alpha-gal as foreign and so produces antibodies against it. In this case the antibody produced is IgE, which is the type of antibody responsible for most allergic reactions. Thus the human is primed for a delayed allergic reaction to subsequent ingestion of "mammalian" meats (not chicken or fish). Alpha-gal in a human can now be recognised through a blood test. Note that those individuals allergic to tick bites

neg: Egg allergy egg products by allergic individuals varies depending on the sensitivity of the person. An antihistamine such as diphenhydramine (Benadryl) may be prescribed. Sometimes prednisone will be prescribed to prevent a possible late phase Type I hypersensitivity reaction. Severe allergic reactions (anaphalaxis) may require treatment with an epinephrine pen, i.e., an injection device designed to be used by a non-healthcare professional when emergency treatment is warranted. A second dose is needed in 16-35% of episodes. There is active research on trying oral immunotherapy (OIT) to desensitize people to egg allergens. A Cochrane Review concluded that OIT can desensitize people, but it

neg: Fernandez reaction Fernandez reaction The Fernandez reaction is a reaction that occurs to signal a positive result in the lepromin skin test for leprosy. The reaction occurs in the skin at the site of injection if the body possesses antibodies to the summu antigen, one of the antigens found in Mycobacterium leprae, the bacteria that causes leprosy. The reaction occurs via a delayed-type hypersensitivity mechanism. This reaction occurs within 48 hours of injection of lepromin and is seen in only tuberculoid forms of leprosy. In contrast, the Mitsuda reaction( delayed granulomatous lesion) occurs 3-4 weeks after injection of lepromin and is only

neg: Allergic bronchopulmonary aspergillosis E, or IgE) and a type III hypersensitivity response (with formation of immunoglobulin G, or IgG). The reaction of IgE with "Aspergillus" antigens results in mast cell degranulation with bronchoconstriction and increased capillary permeability. Immune complexes (a type III reaction) and inflammatory cells are deposited within the mucous membranes of the airways, leading to necrosis (tissue death) and eosinophilic infiltration. Type 2 T helper cells appear to play an important role in ABPA due to an increased sensitivity to interleukin (IL) 4 and IL-5. These cytokines up-regulate mast cell degranulation, exacerbating respiratory decline. "Aspergillus" also utilises a number of factors

neg: Rhinitis rhinitis, non-allergic rhinitis with eosinophilia syndrome (NARES) and idiopathic (vasomotor or non-allergic, non-infectious perennial allergic rhinitis (NANIPER), or non-infectious non-allergic rhinitis (NINAR). In vasomotor rhinitis, certain nonspecific stimuli, including changes in environment (temperature, humidity, barometric pressure, or weather), airborne irritants (odors, fumes), dietary factors (spicy food, alcohol), sexual arousal, exercise, and emotional factors trigger rhinitis. There is still much to be learned about this, but it is thought that these non-allergic triggers cause dilation of the blood vessels in the lining of the nose, which results in swelling and drainage. Non-allergic rhinitis can co-exist with allergic rhinitis, and is referred

neg: Crotalidae polyvalent immune fab patient. Untreated, the snake venom can cause severe pain and tissue damage that can result in the loss of a limb or even death. Prompt (within six hours of snake bite) treatment with CroFab is recommended. 'Fab' refers to Fragment Antigen-Binding, the active mechanism for this antivenom. The most common adverse events reported in clinical studies were mild or moderate reactions involving the skin and appendages (primarily urticaria, rash, or pruritus), which occurred in 14 out of 42 patients. Three patients experienced a serious adverse event. Two patients had a severe allergic reaction (severe hives and a severe rash and