Definition of allergy Allergy

/æˈlɚʤi/ - [atlerjee] - al•ler•gy

We found 8 definitions of allergy from 5 different sources.

What does allergy mean?

Noun Plural: allergies
allergy - hypersensitivity reaction to a particular allergen; symptoms can vary greatly in intensity
		allergic reaction
		hypersensitivity reaction an inappropriate and excessive reaction to an allergen (as pollen or dust or animal hair or certain foods); severity ranges from mild allergy to severe systemic reactions leading to anaphylactic shock
		food allergy allergic reaction to a substance ingested in food
		atopic allergy, atopy, immediate allergy, type i allergic reaction an allergic reaction that becomes apparent in a sensitized person only minutes after contact
		serum disease, serum sickness a delayed allergic reaction to the injection of an antiserum caused by an antibody reaction to an antigen in the donor serum

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allergy (Noun)
A disorder of the immune system causing adverse reactions to substances allergens not harmful to most and marked by the body's production of histamines and associated with atopy, anaphylaxis, and asthma.
allergy (Noun)
Any condition of hypersensitivity to a substance.
allergy (Noun)
Altered susceptibility to a first treatment as exhibited in reaction to a subsequent one.
allergy (Noun)
An antipathy, as toward a person or activity.

allergy
A condition of abnormal sensitivity in certain individuals to contact with substances such as proteins, pollens, bacteria, and certain foods. This contact may result in exaggerated physiologic responses such as hay fever, asthma, and in severe enough situations, anaphylactic shock.\n(Source: KOREN)

An allergy is when someone cannot have a certain thing enter his or her body without getting sick. The person's body attacks that thing the same way it attacks bacteria, or germs. We say the person is "allergic" to that thing. A person can be allergic to food, to certain substances like latex, to insect stings, or to invisible particles floating through the air. These particles can come from plants(pollen), pets(fur), or dust(dust mites).

Allergic reactions.

When people come in contact with something they are allergic to, there can be many different reactions. Their eyes may become very itchy, and their noses may become drippy or stuffy. They may cough and sneeze. They may develop a rash called hives. Their faces may swell up. If it is a food allergy, the person may get an upset stomach. Sometimes a person's esophagus, or throat, may swell up so much that the person can no longer breathe. This is called anaphylaxis. When this happens, a doctor must give the person a medicine called epinephrine to make the swelling go down. Some people with allergies to very common things, like bee stings or fish, carry this medicine with them so it can be used quickly in an emergency. The device they use to inject the medicine is called an EpiPen.