wheal and flare reaction


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wheal

 [hwēl]
a localized area of edema on the body surface, often with severe itching but usually of brief duration; it is the typical lesion of urticaria.
wheal and erythema reaction (wheal and flare reaction) the characteristic local cutaneous reaction consisting of an elevated, blanched wheal surrounded by a spreading “flare” of erythema that occurs within a few minutes at the site of a minor nonpenetrating skin injury and also in response to administration of allergen to an atopic individual; it is caused by release of histamine from mast cells.

wheal and flare reaction

The response within 10 to 15 min to an antigen injected into the skin. The injected skin elevates and blanches, and becomes surrounded by a red rim of inflamed tissue.

wheal

a localized area of edema on the body surface, often attended with severe itching and usually evanescent. It is the typical lesion of urticaria.

wheal and flare reaction
a central blanching surrounded by an erythematous zone of varying diameter, sometimes with pseudopodia, observed on the skin in response to intradermal exposure to allergen (antigen). A basis for detecting particular immediate hypersensitivities in an individual. Produced following release of histamine from mast cells bearing IgE bound to Fc receptor.