wheal-and-flare reaction


Also found in: Acronyms.

wheal-and-er·y·the·ma re·ac·tion

the characteristic immediate reaction observed in an allergy skin test; within 10-15 minutes after injection of antigen (allergen), an irregular, blanched, elevated wheal appears, surrounded by an area of erythema (flare).

wheal-and-flare reaction

Etymology: AS, walu + flare + ME, fleare, to blaze up; L, re, again, agere, to act
a skin eruption that may follow injury or injection of an antigen. It is characterized by swelling and redness caused by a release of histamine. The reaction usually occurs in three stages, beginning with the appearance of an erythematous area at the site of injury, followed by development of a flare surrounding the site; finally a wheal forms at the site as fluid leaks under the skin from surrounding capillaries.

wheal-and-flare reaction

Triple response of Lewis Immunology A series of 3 sequential responses that occur in skin subjected to minor trauma, caused by tissue release of histamine; WFR tests immediate hypersensitivity–'reaginic' or allergic reaction to an antigen, and can be transferred to a nonallergic person. See P-K test.

wheal-and-er·y·the·ma re·ac·tion

(wēl er'i-thē'mă rē-ak'shŭn)
The characteristic immediate reaction observed in the skin test; within 10-15 minutes after injection of antigen (allergen), an irregular, blanched, elevated wheal appears, surrounded by an area of erythema (flare).
Synonym(s): wheal-and-flare reaction.

wheal-and-flare reaction (wēlˑ -and-flerˈ rē·akˑ·shn),

n a three-stage reaction that develops on the surface of the skin because of injury or exposure of the body to an antigen via injection. The condition is characterized by redness and swelling that results from release of histamine.
Enlarge picture
Wheal-and-flare reaction.