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&---

ANAPHYLAXIS PREVENTION 

Anaphylaxis  is a frightening experience. If you have had one anaphylactic reaction, you are at increased risk for another. It is normal  to be anxious about this. The following steps can help to  reduce the risk  of a future anaphylactic reaction: 

See an allergist  — anyone who has experienced an anaphylactic reaction  should be evaluated by a doctor with specific training and experience in the diagnosis and treatment of anaphylaxis. Board-certified allergists have such training and experience. 

Testing  to determine  the trigger  —  It is important to try to confirm  the cause of  the anaphylactic reaction. Allergists can perform  and interpret skin tests  to confirm  your specific anaphylaxis triggers. 

For  the most reliable results, skin tests should be performed at least three to four weeks after an anaphylactic reaction, because if done too soon after  the event, such tests may give negative results when  the person truly does have an allergy. Antihistamines and certain other medications need to be stopped for at least four days before these tests are performed. 

Blood tests can be performed immediately  after an anaphylactic reaction and medications  do not interfere with the results. 

In some cases, allergy tests do not identify any specific trigger. This condition is called idiopathic anaphylaxis. It is more common in adults than  in children. An allergist can provide the best advice  about how to manage this condition. 

Avoiding triggers  — when  a trigger  has been identified, you should avoid  it. However, avoiding some triggers, such as common foods, can be difficult to avoid. 

Foods —  If you have experienced an anaphylactic reaction due  to a food, you should eliminate that food from your diet. This requires that you read and understand food labels and ask about  the preparation and content  of all foods eaten when  away from home. This recommendation applies  to everything that you plan to eat, not just  the foods  that are most likely  to contain  the trigger. More information about food allergy treatment and prevention is available separately. 

An allergist can provide strategies for identifying allergens in processed foods and when dining out. In addition, practical information is available online  from the Food Allergy  and Anaphylaxis Network. 

Insect stings  — People with an allergy  to a stinging insect (bees, yellow jackets, wasps, hornets,  or fire ants) should wear protective clothing, including closed shoes, and, if allergic  to yellow jackets, should avoid drinking from open beverage containers  and eating outdoors. 

A course  of allergy shots is recommended for anyone who has had an anaphylactic reaction after  an insect sting. The injections are given  over several years. They dramatically reduce  the person's risk of another episode of anaphylaxis. 

Medications — if you have an allergy to  a medication,  you should learn all  the names  of that  medication and the settings  in which you are likely  to encounter it. Ask  your healthcare providers to note  your allergy in your medical record and on your medical identification device. 

Wear medical identification  — People who have experienced an anaphylactic reaction should wear a medical identification bracelet or similar medical identification tag  at all times.  If another reaction occurs and you are too ill to explain your condition,  the words "anaphylaxis"  or "anaphylactic reaction" will help  emergency responders provide prompt and proper care. 

The tag  should include a list of known allergies, as well as  the names  and phone numbers of emergency contacts. One device, Medic Alert®, provides a toll-free number that emergency medical workers can call  to find out a person's medical history, list of medications, emergency contact numbers, and healthcare provider  names and numbers.