Selective IgA deficiency


Selective IgA deficiency is the lack of a disease-fighting antibody in the immune system called immunoglobulin A (IgA). People with this condition usually have typical levels of other immunoglobulins (im-u-no-GLOB-u-lins).

An immunoglobulin is an antibody produced by immune system cells to fight bacteria, parasites and other agents that cause illness. IgA antibodies circulate in the blood and are found in tears, saliva, breast milk, and fluids released from the lining of the airways, lungs and digestive system.

Most people with selective IgA deficiency have no symptoms. But some people who have selective IgA deficiency have frequent illness of the airways, lungs and digestive system.

Selective IgA deficiency may increase the risk of other conditions related to the immune system, such as allergies, asthma, rheumatoid arthritis, inflammatory bowel diseases and others.

There is no treatment specifically for selective IgA deficiency. Treatments focus on addressing the frequent, repeat or long-lasting conditions that develop with this immune system disorder.


Most people with selective IgA deficiency have no symptoms. Some people have illnesses more often than is typical. They also may have a particular illness that returns often. Having frequent illnesses doesn't necessarily mean a person has selective IgA deficiency.

People with selective IgA deficiency may have frequent or repeat episodes of the following:

  • Ear infections, particularly in young children.
  • Colds.
  • Sinus infections.
  • Lung illnesses, such as bronchitis or pneumonia.
  • Giardiasis, a parasitic illness of the digestive system that causes diarrhea.

Children with frequent illnesses may not eat well or may not gain weight typical for their age.


Selective IgA deficiency happens when immune system cells don't produce any or produce very few IgA antibodies. The exact reason cells don't produce these antibodies isn't known.

Certain medicines used to treat seizures, epilepsy or rheumatoid arthritis may cause selective IgA deficiency in some people. The deficiency may continue after the medicine is no longer taken.

Risk factors

A family history of selective IgA deficiency increases the risk of the condition. Certain variations of genes appear to be linked to selective IgA deficiency, but no gene is known to directly cause the condition.


People with selective IgA deficiency are at increased risk of other long-term conditions. These include:

  • Allergies and asthma.
  • Rheumatoid arthritis.
  • Celiac disease.
  • Inflammatory bowel disease.
  • Common variable immunodeficiency, which is a lack of two or more types of immunoglobulins.

Risk of reaction to blood products

People with selective IgA deficiency are at risk of reactions to blood transfusions or blood products. Because a person's body doesn't make IgA, the immune system may see it as a foreign substance in a blood transfusion or other treatment with blood products.

A reaction may cause high fever, chills, sweating and other symptoms. Rarely, people with selective IgA deficiency have a life-threatening allergic reaction, called anaphylaxis (an-uh-fuh-LAK-sis).

Healthcare professionals recommend wearing a medical bracelet. A bracelet can show that you have selective IgA deficiency and should receive modified blood or blood products.


A diagnosis of selective IgA deficiency is based on a blood test that measures levels of immunoglobulins in the blood. IgA deficiency can be complete or partial.

Your healthcare professional may order an immunoglobulin blood test because you have had frequent or repeat illnesses. The test also may be a part of a series of lab tests to diagnose or rule out other conditions.


Antibiotic treatments are prescribed as needed to treat bacterial disease. If you have had a long-term illness, such as chronic bronchitis, you may receive antibiotics as a preventive treatment. This therapy is called antibiotic prophylaxis (pro-fuh-LAK-sis).

Preparing for an appointment

You may start by seeing your primary healthcare professional. You may be referred to a specialist in immune system disorders called an immunologist.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do in advance. Also make a list of:

  • Symptoms, including any that don't seem related to the reason for the appointment.
  • Key personal information, including major stresses, recent life changes and family medical history.
  • All medicines, vitamins or other supplements you take, the doses of each and the reason for taking each one.
  • Questions to ask your healthcare professional.

Take a family member or friend along, if possible, to help you remember information you receive.

Questions you might ask if you have experienced frequent or repeat illnesses include:

  • What are the possible causes of these frequent illnesses?
  • What tests will I need?
  • What are possible treatment plans?
  • I have other health conditions. How can I best manage them together?
  • Should I see a specialist?
  • Are there brochures or other printed material I can have? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Your healthcare professional is likely to ask you several questions, such as:

  • What symptoms have you had?
  • What illnesses have you been diagnosed with in the past?
  • How often have you had these illnesses in the past year?
  • What treatments have you had for previous illnesses?
  • Is there a history of immune system disorders in your family?

Content From Mayo Clinic Updated: 05/23/2024
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