IgA Deficiency

Also known as: selective IgA deficiency, immunoglobulin A deficiency

What is IgA Deficiency?

Immunoglobulin A, or IgA, is an antibody that is found primarily within the tissues of the body. Along with other antibodies (such as IgM and IgG) it helps to fight infections. IgA Deficiency is the most common immunodeficiency, and a majority of people who have this are asymptomatic. Some people with IgA deficiency can have more frequent sinopulmonary infections (sinus infections, bronchitis, pneumonia, etc), and are more likely to have giardia infection, and autoimmune diseases. If a person with IgA deficiency does not have any IgA, they are at an increased risk of developing an allergic reaction to blood transfusion products, and should use IgA depleted blood products.

What might cause IgA Deficiency?

There are known genetic mutations that are associated with IgA Deficiency, but there is no specific cause that we know of. If you have relatives with IgA deficiency, you are more likely to have IgA deficiency.

How can it be treated?

A majority of patients with IgA deficiency are asymptomatic, and do not need to take specific precautions. You should be evaluated by a board certified Allergist/Immunologist to determine if you need to take special precautions with blood transfusions. Your Allergist/Immunologist may also want to monitor blood work on a regular basis.

When should you seek medical attention?

You should see a board certified Allergist/Immunologist if you have been found to have low or absent IgA on blood work, if you have recurrent sinopulmonary infections, giardia infection, celiac disease, family history of IgA deficiency, or an anaphylactic reaction to a blood transfusion.

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Reviewed by: Amy Feldman, MD

This page was last updated on: September 16, 2025 12:51 PM