allergy

n.
a disorder in which the body becomes hypersensitive to particular antigens (called allergens), which provoke characteristic symptoms whenever they are subsequently inhaled, ingested, injected, or otherwise contacted. Normally antibodies in the bloodstream and tissues react with and destroy specific antigens without further trouble. In an allergic person, however, the allergens provoke the release of a class of antibodies (IgE) that become bound to mast cells in the body's tissues. The subsequent reaction of allergen with tissue-bound antibody (see reagin) also leads, as a side-effect, to cell damage, release of histamine and serotonin (5-hydroxytryptamine), inflammation, and all the symptoms of the particular allergy. Different allergies afflict different tissues and may have either local or general effects, varying from asthma and hay fever to severe dermatitis or gastroenteritis or extremely serious shock (see anaphylaxis).
Derivatives:
allergic adj.

The new mediacal dictionary. 2014.

Look at other dictionaries:

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  • allergy — n. 1. hypersensitivity to a particular substance. an allergy to bee venom so severe that a second sting may be fatal [WordNet 1.5] || …   The Collaborative International Dictionary of English

  • allergy — dated from the early 20c in its pathological meaning ‘sensitiveneness to pollen, certain foods, antibiotics, etc.’ It is attested earlier in German (Allergie) and is derived from Greek words allos ‘other, different’ and ergon ‘work’. Its extended …   Modern English usage

  • allergy — allergy. См. атопия. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • allergy — (n.) 1911, from Ger. Allergie, coined 1906 by Austrian pediatrician Clemens E. von Pirquet (1874 1929) from Gk. allos other, different, strange (see ALIAS (Cf. alias) (adv.)) + ergon activity (see URGE (Cf. urge) (v.)) …   Etymology dictionary

  • allergy — [n] reaction to certain food, material, etc. allergic reaction, aversion, hay fever, hypersensitivity, sensitivity, susceptibility, vulnerability; concepts 405,410 …   New thesaurus

  • allergy — ► NOUN (pl. allergies) ▪ an adverse reaction by the body to a substance to which it has become hypersensitive. DERIVATIVES allergist noun. ORIGIN from Greek allos other …   English terms dictionary

  • allergy — ☆ allergy [al′ər jē ] n. pl. allergies [Ger allergie < Gr allos, other (see ELSE) + ergeia, as in energeia (see ENERGY)] 1. a hypersensitivity to a specific substance (such as a food, pollen, dust, etc.) or condition (as heat or cold) which in …   English World dictionary

  • allergy — noun ADJECTIVE ▪ food ▪ milk, nut, peanut, penicillin, pollen, etc. ▪ respiratory ▪ …   Collocations dictionary

  • allergy — 1. Hypersensitivity caused by exposure to a particular antigen (allergen) resulting in a marked increase in reactivity to that antigen upon subsequent exposure, sometimes resulting in harmful immunologic consequences. SYN: acquired sensitivity,… …   Medical dictionary

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