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Allergies Glossary

Terms used to explain Allergies can sometimes be confusing. To help you fully understand the articles and features related to this very important health topic, we have compiled a glossary of terms that can help.


Pronunciation: \ˌant-i-ˈhis-tə-ˌmēn, ˌan-ˌtī-, -mən\

Function: adjective
: tending to block or counteract the physiological action of histamine <human blood lacks antihistamine[1] activity>


Pronunciation: \ˈat-ə-pē\

Function: noun
pl -pies
: a prob. hereditary allergy characterized by symptoms (as asthma, hay fever, or hives) produced upon exposure esp. by inhalation to the exciting environmental antigen

B Cell

B cell
Function: noun
: any of the lymphocytes that have antigen-binding antibody molecules on the surface, that comprise the antibody-secreting plasma cells when mature, and that in mammals differentiate in the bone marrow —called also B lymphocyte, compare t cell


Pronunciation: \ˌdē-kən-ˈjes-tənt\
Function: noun
1: an agent that relieves congestion (as of mucous membranes)


Pronunciation: \ig-ˈzē-mə, ˈeg-zə-mə, ˈek-sə-\

Function: noun
: an inflammatory condition of the skin characterized by redness, itching, and oozing vesicular lesions which become scaly, crusted, or hardened


Pronunciation: \i-ˌlim-ə-ˈnā-shən\

Function: noun

1: the act of discharging or excreting waste products or foreign substances from the body
2eliminationspl: bodily discharges including urine, feces, and vomit
3: the removal from a molecule of the constituents of a simpler molecule <ethylene is formed by the elimination of water from ethanol>


Pronunciation: \ˈhep-ə\

Function: adjective
Etymology: high efficiency particulate air
: being, using, or containing a filter usu. designed to remove 99.97% of airborne particles measuring 0.3 microns or greater in diameter passing through it <HEPA filters> <HEPA vacuum cleaners>

Hay Fever

hay fever
Pronunciation: \ˈhā-ˌfē-vər\

Function: noun
: an acute allergic reaction to pollen that is usu. seasonal and is marked by sneezing, nasal discharge and congestion, and itching and watering of the eyes —called also pollinosis


Pronunciation: \ˈhis-tə-ˌmēn, -mən\

Function: noun
: a compound C5H9N3 esp. of mammalian tissues that causes dilatation of capillaries, contraction of smooth muscle, and stimulation of gastric acid secretion, that is released during allergic reactions, and that is formed by decarboxylation of histidine


Pronunciation: \ˈhīvz\

Function: noun plural but singular or plural in construction
: an allergic disorder marked by raised edematous red patches of skin or mucous membrane and usu. by intense itching and caused by contact with a specific precipitating factor (as a food, drug, or inhalant) either externally or internally —called also urticaria


Pronunciation: \ˈhī-ˌjēn also hī-ˈ\

Function: noun

1: a science of the establishment and maintenance of health see industrial hygiene mental hygiene
2: conditions or practices (as of cleanliness) conducive to health


Pronunciation: \-ˈther-ə-pē\

Function: noun
pl -pies
: treatment of or prophylaxis against disease by attempting to produce active or passive immunity —called also immune therapy


Pronunciation: \ˈir-ə-tənt\

Function: adjective
: causing irritation; specif: tending to produce inflammation


Pronunciation: \ˌlü-kə-ˈtrī-ˌēn\

Function: noun
: any of a group of eicosanoids that are generated in basophils, mast cells, macrophages, and human lung tissue by lipoxygenase-catalyzed oxygenation esp. of arachidonic acid and that participate in allergic responses (as bronchoconstriction in asthma) see slow-reacting substance of anaphylaxis

Mast Cell

mast cell
Pronunciation: \ˈmast-\

Function: noun
: a granulocyte that occurs esp. in connective tissue and has basophilic granules containing substances (as histamine and heparin) which mediate allergic reactions

Patch Test

patch test
Function: noun
: a test for determining allergic sensitivity that is made by applying to the unbroken skin small pads soaked with the allergen to be tested and that indicates sensitivity when irritation develops at the point of application compare intradermal test prick test scratch test

Plasma Cell

plasma cell
Function: noun
: a lymphocyte that is a mature antibody-secreting B cell

Prick Test

prick test
Pronunciation: \ˈprik-\

Function: noun
: a test for allergic susceptibility made by placing a drop of the allergy-producing substance on the skin and making breaks in the skin by lightly pricking the surface (as with a pin) compare intradermal test patch test scratch test


Pronunciation: \rī-ˈnīt-əs\

Function: noun
pl -nit*i*des
Pronunciation: \-ˈnit-ə-ˌdēz\
: inflammation of the mucous membrane of the nose marked esp. by rhinorrhea, nasal congestion and itching, and sneezing; also: any of various conditions characterized by rhinitis see allergic rhinitis rhinitis medicamentosa rhinitis sicca vasomotor rhinitis

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© 2011 Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Inc.

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