Allergic Reaction Causes

Almost anything can trigger an allergic reaction.

• The body's immune system involves the white blood cells, which produce antibodies.



• When the body is exposed to an antigen, a complex set of reactions begins.



• The white blood cells produce an antibody specific to that antigen. This is called "sensitization."



• The job of the antibodies is to detect and help destroy substances that cause disease and sickness. In allergic reactions, the antibody is called immunoglobulin E or IgE.

• This antibody promotes production and release of chemicals and hormones called "mediators."



• Mediators have effects on local tissue and organs in addition to activating more white blood cell defenders. It is these effects that cause the symptoms of the reaction.



• Histamine is one of the better-known mediators produced by the body.



• If the release of the mediators is sudden or extensive, the allergic reaction may also be sudden and severe, and anaphylaxis may occur.

• Your allergic reactions are unique to you. For example, your body may have learned to be allergic to shellfish or other foods from repeated exposure.

• Most people are aware of their particular allergy triggers and reactions.



• Certain foods, vaccines and medications, latex rubber, aspirin, shellfish, dust, pollen, mold, animal dander, and poison ivy are well-known allergens.



• Bee stings, fire ant stings, penicillin, and peanuts are known for causing dramatic reactions that can be serious and involve the whole body.



• Minor injuries, hot or cold temperatures, exercise, or even emotions may be triggers of allergic reactions.



• Often, the specific allergen cannot be identified unless you have had a similar reaction in the past.

• Allergies and the tendency to have allergic reactions run in some families. You may have allergies even if they do not run in your family.



• Many people who have one trigger tend to have other triggers as well.



• People with certain medical conditions are more likely to have allergic reactions:



• severe allergic reaction in the past



• asthma



• lung conditions that affect breathing, such as chronic obstructive pulmonary disease (COPD)



• nasal polyps



• frequent infections of the nasal sinuses, ears, or respiratory tract



• sensitive skin