allergen

[al-er-juh n, -jen] /ˈæl ər dʒən, -ˌdʒɛn/
noun, Immunology
1.
any substance, often a protein, that induces an allergy: common allergens include pollen, grasses, dust, and some medications.
Origin
1910-15; aller(gy) + -gen
Examples from the web for allergen
  • While some individuals build up immunities from multiple exposures to an allergen, others will develop sensitivities.
  • It's a deadly allergen to some people, but irresistible to rodents.
  • It turns out that a fragrance used in many shampoos is a common allergen that may even cause eczema.
  • The researchers found there were no differences in allergen levels between hypoallergenic dogs and non-hypoallergenic ones.
  • However, some reactions can occur after several hours, particularly if the allergen causes a reaction after it has been eaten.
  • The patient may receive skin or blood allergy tests, particularly if a specific allergen is suspected and available for testing.
  • It may disappear on its own when the allergen that caused it is removed.
  • The discovery makes shrimp one of a few allergenic foods for which the actual allergen has been purified and identified.
  • allergen immunotherapy: a practice parameter second update.
  • The products contain egg, an allergen, which is not noted on the label.
British Dictionary definitions for allergen

allergen

/ˈæləˌdʒɛn/
noun
1.
any substance capable of inducing an allergy
Derived Forms
allergenic, adjective
allergenicity, noun
Word Origin and History for allergen
n.

substance causing allergy, 1912, from allergy on model of antigen.

allergen in Medicine

allergen al·ler·gen (āl'ər-jən)
n.

  1. A substance, such as pollen, that causes an allergy.

  2. See antigen.

al'ler·gen'ic (-jěn'ĭk) adj.
allergen in Science
allergen
  (āl'ər-jən)   
A substance, such as pollen, that causes an allergic reaction.
Encyclopedia Article for allergen

substance that in some persons induces the hypersensitive state of allergy and stimulates the formation of reaginic antibodies. Allergens may be naturally occurring or of synthetic origin and include pollen, mold spores, dust, animal dander, insect debris, foods, blood serum, and drugs. Identification of allergens is made by studying both the site of symptoms (e.g., inhalants such as molds, pollens, and dander usually affect the eyes, nose, and bronchi; cosmetics often affect the skin of the face and hands) and the time that symptoms appear (e.g., seasonal allergy to pollen). See also antigen; reagin.

Learn more about allergen with a free trial on Britannica.com