Allergies Health Center

Allergic Reaction Causes

 Many substances 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  substance that causes the immune system to make antibodies against it -- 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, medications, latex, 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 in some people 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  

  • Sensitive skin