Allergic Reaction Causes

Almost anything can trigger an allergic reaction.

 
The body's immune system has a patrol of 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 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." 

 
Histamine is one well-known mediator. 

 
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. 

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

 
Your allergic reactions are unique to you. For example, your body may have learned to be allergic to poison ivy 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 famous 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. 

 
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