Low IgA Levels in children: Information for parents and families

What is IgA?

IgA, or immunoglobulin A, is one of the three main classes of antibodies (IgA, IgG and IgM) produced by immune cells in our body called B cells. The role of antibodies is to help our body fight against infection and prevent future infection occurring. IgA is an antibody which is found mostly in the inner lining of the nose, airways and the gut as well as in secretions such as saliva, tears and breastmilk.

What does a low IgA level mean?

A very low level, or absence, of IgA in the blood is very common and is found in around 1 in 170 to 1 in 400 children1. A low IgA level or absence of IgA may be picked up when blood tests are undertaken for other reasons for example where the test is based on an IgA antibody, so the level of total IgA is also checked, such as to test if a person has coeliac disease. In the majority of cases (85%) there are no symptoms and the low IgA level does not cause any problems as the rest of the immune system can compensate.

At birth, there is very little IgA produced by the immune system, this gradually increases over the first months of life but takes several years to rise to adult levels. Therefore it is common for children under four years old to have a level which the laboratory will highlight as low. It takes time for the body’s immune system to develop the IgA to a normal level so a permanent low IgA cannot be diagnosed in very young children. If a child under four years old is found to have low IgA they do not need to have this test repeated routinely. The cause of a low IgA is not fully understood or why some people with a low IgA have symptoms whereas most do not.

What are the symptoms of IgA deficiency?

A low IgA is sometimes called IgA deficiency even though it rarely causes problems. In those children who have symptoms, these are usually of recurrent respiratory (chest) and gastrointestinal (gut) infections. Autoimmune conditions such as coeliac disease are more common in children with low IgA and low IgA may more rarely be the first sign of a broader antibody deficiency (other antibodies such as IgG might go on to be affected). Allergic conditions such as allergic rhinoconjunctivitis (hayfever) may be more common in those with low IgA. Your doctor will ask you questions about your child’s general health and recurrent infections to help decide if your child has any symptoms related to IgA deficiency.

What is the treatment for low IgA levels?

As mentioned above, often no treatment is needed as there are no problems caused by the low or absent IgA level. These children usually do not need any treatment or follow up but parents and carers should be aware that if their child has more frequent or severe infections than expected their child needs to be reviewed. In those patients that need treatment, this is usually with prompt use of antibiotics early on in an infection.

Can my child have the usual childhood immunisations?

In isolated low IgA levels (where there is no other problem with the immune system) there is no reason not to have the usual childhood immunisations. It is important to discuss any concerns you have with your child’s doctor.

Further information

• Primary immunodeficiency UK (opens in a new tab)