Definition

Selective deficiency of IgA is the most common immune deficiency disorder. People with this disorder have a low or absent level of a blood protein called immunoglobulin A.

Alternative Names

IgA deficiency; Immunodepressed - IgA deficiency; Immunosuppressed - IgA deficiency; Hypogammaglobulinemia - IgA deficiency; Agammaglobulinemia - IgA deficiency

Causes

Selective IgA deficiency is usually inherited, which means it is passed down through families. However, there are also cases of drug-induced selective IgA deficiency.

It may be inherited as an autosomal dominant or autosomal recessive trait. It is usually found in people of European origin. It is less common in people of other ethnicities.

Symptoms

Many people with selective IgA deficiency have no symptoms.

If a person does have symptoms, they may include frequent episodes of:

• Bronchitis (airway infection)
• Chronic diarrhea
• Conjunctivitis (eye infection)
• Gastrointestinal inflammation, including ulcerative colitis, Crohn disease, and a sprue-like illness
• Mouth infection
• Otitis media (middle ear infection)
• Pneumonia (lung infection)
• Sinusitis (sinus infection)
• Skin infections
• Upper respiratory tract infections

Other symptoms include:

• Bronchiectasis (a disease in which the bronchial tubes in the lungs become damaged and enlarged)
• Asthma without a known cause

Exams and Tests

There may be a family history of IgA deficiency. Tests that may be done include:

• IgG subclass measurements
• Quantitative immunoglobulins
• Serum immunoelectrophoresis

Treatment

No specific treatment is available. Some people gradually develop normal levels of IgA without treatment.

Treatment involves taking steps to reduce the number and severity of infections. Antibiotics are often needed to treat bacterial infections.

For people with more frequent or severe infections, immunoglobulins might be given through a vein or by injection to boost the immune system.

Autoimmune disease treatment is based on the specific problem.

Note: People with complete IgA deficiency may develop anti-IgA antibodies if given blood products and immunoglobulins. This may lead to allergies or life-threatening anaphylactic shock. However, they can safely be given IgA-depleted immunoglobulins.

Outlook (Prognosis)

Selective IgA deficiency tends to be less severe than many other immunodeficiency diseases.

Many people with selective IgA deficiency have no symptoms at all. Some people with IgA deficiency will recover on their own and produce IgA in larger quantities over a period of years.

Possible Complications

Autoimmune disorders such as rheumatoid arthritis, systemic lupus erythematosus, and celiac disease may develop.

People with IgA deficiency may develop antibodies to IgA. As a result, they can have severe, even life-threatening reactions to transfusions of blood and blood products.

When to Contact a Medical Professional

People with IgA deficiency should contact their health care provider if they are having symptoms of an infection or intestinal symptoms.

Prevention

Genetic counseling may be of value to prospective parents with a family history of selective IgA deficiency.

References

Cunningham-Rundles C. Primary immunodeficiency diseases. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 231.

Hernandez-Trujillo VP, Ortega C. B-cell and antibody deficiencies. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 166.