allergic reactions


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allergic reactions

acute inflammatory skin hypersensitivity reaction (redness, tissue oedema, pruritus) induced by the histamine released from local mast cells in response to allergen contact in susceptible individuals (Table 1)
Table 1: Classification of types of hypersensitivity reactions
Type IType IIType IIIType IVType V
AntigenPollens, moulds, mites, drugs, foods, parasitesCell surface moietiesBacteria, fungi, parasitesCell or tissue moietiesCell surface receptors
MediatorsIgE and mast cellsIgG, IgM, complementIgG, IgM, IgA, complementT-cell-activated macrophages and lymphokinesIgG
TestsSkin tests (wheal and flare)Coombs' test
Red cell agglutination
Antibody precipitation
Immune complexesSkin test (erythema, induration)Indirect immunofluorescence
Time to reaction5-10 minutes6-36 hours4-12 hours48-72 hoursVariable
HistologyOedema, vasodilatation, mast cell deregulation, eosinophilsTarget cell damageAcute inflammation, neutrophils, vasculitisPerivascular inflammation, mononuclear cells, granuloma, caseation and necrosis in TBNormal or hypertrophy
Characteristic diseasesExtrinsic asthma, atopic eczema, allergic rhinitis, anaphylaxisHaemolytic anaemia, transfusion reactions, HDN, Goodpasture's syndrome, addisonian pernicious anaemia, myasthenia gravisAutoimmune disease (RA, SLE, glomerulonephritis)
Low-grade persistent infection (viral hepatitis)
Environmental diseases (farmer's lung)
Pulmonary TB, contact dermatitis, graft-versus-host disease, insect bites, Hansen's diseaseGraves, disease, myasthenia gravis
TreatmentAntigen avoidance
Topical corticosteroids
Sodium cromoglicate
Exchange transfusion, plasmapheresis, immunosuppressivesCorticosteroids, immunosuppressives, plasmapheresisImmunosuppressives, cortico-steroids, antigen removalTreatment of presenting disease

Ig, immunoglobulin; TB, tuberculosis; HDN, haemolytic disease of the newborn; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus.

hypersensitivity

An excessive reaction, local or systemic, or inappropriate immune response to an antigen. Four types of immune responses are usually described, but the main reaction involving the eyes is type 1. They are also called allergic reactions types 1-4.
type 1 hypersensitivity An immediate, abnormal reaction occurring when an antigen reacts with an antibody (e.g. immunoglobulin E (IgE)) attached to a mast cell or basophil. This leads to the release of specific chemical mediators of allergy (e.g. histamine) that react with target organs throughout the body. Systemic signs include: itching, lacrimation, skin rash and possibly haemodynamic collapse and shock. Allergic conjunctivitis is an example of this type of hypersensitivity.
Type 2 h . (cytotoxic h.) is caused by an interaction of antibody and antigens on cell surfaces. Examples: Graves' disease, myasthenia gravis. Type 3 h. (immune-complex mediated h.) is mediated by a combination of antigen-antibody. Example: systemic lupus erythematosus. Type 4 h. (T cell-mediated h.) is a delayed reaction (several days to develop) mediated by T lymphocytes. Example: rheumatoid arthritis. See antihistamine; mast cell stabilizers.
References in periodicals archive ?
My three-year-old daughter has a nut allergy, and an allergic reaction can be fatal if an epipen is not at hand.
The residual content of monomer (MMA) and formaldehyde after reaction is subjected to cause allergic reactions.
The trust also dealt in 2016/16 with 37 admissions for anaphylactic shock - an extreme and often life-threatening allergic reaction.
If so, an allergic reaction could be reduced or possibly prevented.
According to the company, the pre-filled single dose syringe (PFS) provides a single dose of epinephrine (adrenaline), which is considered the drug of choice for immediate administration in acute anaphylactic reactions to insect stings or bites, allergic reaction to nuts & food, drugs and other allergens, as well as idiopathic or exercised-induced anaphylaxis.
On the other hand, fans can also just take her handlers' word for it and believe she has both a sinus infection and a severe allergic reaction, and she checked herself in a hospital for a week to make sure she recovered fully.
This case might be an important reminder to all medical personnel, that any patients can have allergic reactions to parenteral corticosteroids containing succinate.
In recent years, severe or even fatal allergic reactions to para-phenylene-diamine (PPD), a chemical used in 99% of all hair dyes, have been reported.
The researchers caution that people should not try peanut SLIT on their own because any form of immunotherapy carries a significant risk for allergic reactions.
Rubber gloves are the main source of allergic reactions, although latex is also used in other products such as condoms and some medical devices.
Auvi-Q delivers on this by offering a state-of-the-art epinephrine auto-injector device that addresses the needs of patients at risk for life-threatening allergic reactions and their caregivers.