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Immunoglobulin A Deficiency

Immunoglobulin A (IgA) is a blood protein that's part of your immune system. Your body makes IgA in order to fight off infections.

IgA is found in mucous membranes, especially in the respiratory and gastrointestinal tracts, and in saliva, tears, and breast milk. It appears to play a part in asthma and allergies. Researchers have also linked IgA to autoimmune conditions, in which your body's immune system mistakenly attacks your body itself.

Illustration of the immune system
The Immune System - Click to Enlarge

Facts about immunoglobulin A deficiency

Having an IgA deficiency means that you have low levels of or no immunoglobulin A in your bloodstream. IgA deficiency typically happens in one out of every 300 to 500 people.

IgA deficiency is typically a genetic disorder passed down through families. In rare instances, it can be caused by medicines you're taking.


Most people with an IgA deficiency don't have any symptoms related to the disorder. In these cases, it's found on a blood test, if it's found at all. Some people with an IgA deficiency are more prone to getting certain infections or getting them more often than others. These potential complications can include:

  • Diarrhea

  • Sinusitis

  • Bronchitis

  • Eye infection

  • Ear infection

  • Pneumonia

  • Skin infection

  • Asthma


If you have a family history of IgA deficiency and some of the above symptoms, you might be at risk. Blood tests can be used to see if IgA is absent in your blood.


There is no cure for IgA deficiency, and immunotherapy does not work to treat it. But you can take steps to minimize your risk for illness or infection. These include taking antibiotics whenever illness occurs. If infections are chronic, or ongoing, daily antibiotics may be needed.


Because IgA deficiency is usually an inherited problem, you can't do anything to prevent it. But you can limit the spread of germs and illnesses by washing your hands often and avoiding large crowds, especially during cold and flu season. Also, talk with your health care provider about vaccinations that may help and when you should get them.

If you have immunoglobulin A deficiency and are worried about the risks of passing it on to your children, talk with a genetic counselor about your concerns. 

Online Medical Reviewer: Sohrabi, Farrokh, MD
Online Medical Reviewer: Ziegler, Olivia Walton, MS, PA-C
Date Last Reviewed: 7/26/2012
© 2000-2015 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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