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Definition
An allergy is a reaction by your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Normally, your immune system fights germs. It is your body’s defense system. In most allergic reactions, however, it is responding to a false alarm. Genes and the environment probably both play a role.
Allergies can cause a variety of symptoms such as a runny nose, sneezing, itching, rashes, swelling, or asthma. Allergies can range from minor to severe. Anaphylaxis is a severe reaction that can be life-threatening. Doctors use skin and blood tests to diagnose allergies. Treatments include medicines, allergy shots, and avoiding the substances that cause the reactions. (SOURCE: Medline Plus https://medlineplus.gov/allergy.html)
Example
Allergies to foods such as peanuts, shellfish, wheat, soy, etc. are very common and normally present themselves in the form of hives. Reactions to different chemicals or food colorings also appear as hives. Reactions to various types of pollen and dust also trigger allergic reactions, usually runny noses and watery eyes.
What does it look like?
Video
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