Allergies and Your Immune System

An allergic reaction results when your immune system recognizes a harmless substance (such as a pollen grain) as a foreign invader and acts accordingly. The body responds and produces antibodies (IgE), which recognize and bind to the protein. This immune response is responsible for the allergic reaction.

For example, in the case of a pollen allergy, your immune system will trigger sneezing to rid the body of the allergen, and congestion to prevent more pollen grains from entering the body. You may also become fatigued as your body works overtime fighting the allergen.

The immune system releases a chemical called immunogoblin E (IgE) that in turn triggers the release of histamines. The histamine reaction produces the symptoms associated with allergies.

The severity of the histamine reaction to allergens varies among individuals. Some people have very mild allergies. For others, even a trace amount of a particular allergen is enough to trigger a serious reaction in some people.

Common allergens include:

• bee venom
• certain antibiotics
  
• dust mites
• latex
  
• mold
• peanuts
  
• poison ivy
  
• pollen
• pet dander.

This section is divided into multiple articles covering topics such as common allergens in your home and food allergies, with each listed in the menu to the left. To research other allergy or health topics, please use the morefocus search tool, or see the related topics listed to the left.