Allergy / Hypersensitivity

An allergy is a reaction of your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are

• Pollen

• Dust mites

• Mold spores

• Pet dander

• Food

• Insect stings

• Medicines

How do you get allergies? Scientists think both genes and the environment have something to do with it. 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. Allergies can cause a runny nose, sneezing, itching, rashes, swelling or asthma. Symptoms vary. Although allergies can make you feel bad, they usually won't kill you. However, a severe reaction called anaphylaxis is life-threatening. Food allergy is an abnormal response to a food triggered by your body's immune system. Allergic reactions to food can sometimes cause serious illness and death. Tree nuts and peanuts are the leading causes of deadly allergic reactions called anaphylaxis. In adults, the foods that most often trigger allergic reactions include

• Fish and shellfish, such as shrimp, lobster and crab

• Peanuts

• Tree nuts, such as walnuts

• Eggs

Problem foods for children are eggs, milk (especially in infants and young children) and peanuts.

Sometimes a reaction to food is not an allergy. It is often a reaction called "food intolerance". Your immune system does not cause the symptoms of food intolerance. However, these symptoms can look and feel like those of a food allergy.