Signs parents may notice
- Infections that are unusually frequent, severe or long-lasting
- Two or more pneumonias, or repeated serious ear or sinus infections
- Infections that need intravenous antibiotics or do not clear with usual treatment
- Poor weight gain or growth
- Deep skin or organ abscesses
- Persistent oral thrush after infancy
- Unusual reactions to the BCG vaccine, such as a large swelling or lymph node
- A family history of immune problems or early infant deaths
Tests that may be used
- Complete blood count with differential
- Immunoglobulin levels (IgG, IgA, IgM, IgE)
- Antibody responses to vaccines
- Lymphocyte subsets (flow cytometry)
- Tests of neutrophil function, such as the DHR test
- Genetic testing
What is primary immunodeficiency?
The immune system protects the body from infections. In primary immunodeficiency, now often called inborn errors of immunity (IEI), part of the immune system is missing or does not work properly from birth, usually because of a genetic change. There are hundreds of different types, ranging from mild conditions that cause only extra infections to rare, severe forms that are recognised in early infancy.
“Primary” means the condition is present from birth. This is different from secondary immunodeficiency, which can result from other illnesses, malnutrition or medicines that lower immunity.
Some inborn errors of immunity cause autoimmune or inflammatory problems, such as low blood counts, arthritis or bowel inflammation, rather than, or as well as, infections. This is one reason pediatric rheumatologists are often involved in their evaluation.
Warning signs
Immunodeficiency should be considered if a child has infections that are unusually frequent, severe, long-lasting or caused by unusual germs, or if infections come with poor growth. A family history of similar problems, or of infant deaths from infection, is also important. In India, an unusual reaction to the BCG vaccine can be an early clue.
How is it diagnosed?
Evaluation starts with a detailed history, including infections, vaccinations, growth and family history, and a thorough examination. Initial blood tests include a blood count and immunoglobulin levels. Depending on the findings, more specialised tests look at different parts of the immune system, and genetic testing can identify the exact cause.
How is it treated?
Treatment depends on the type and severity of the immunodeficiency.
- Preventing and treating infections: prompt treatment of infections, and preventive antibiotics or antifungals for some children.
- Immunoglobulin replacement: regular infusions of antibodies for children who cannot make enough of their own.
- Vaccination planning: an individual plan that uses safe vaccines and avoids live vaccines where they could cause harm.
- Treating autoimmune or inflammatory complications when they occur.
- Stem cell transplant or other specialised therapies for some severe forms, at specialist centres.
Genetic counselling helps families understand the condition and plan for the future.
When to see a specialist
If your child has the warning signs above, discuss with your child’s doctor whether an immunology evaluation is needed. Early diagnosis allows treatment that can prevent serious infections and long-term damage, particularly to the lungs.
Treatment options that may be considered
- Prompt treatment of infections
- Preventive antibiotics or antifungals
- Immunoglobulin replacement therapy
- Individualised vaccination plan
- Treatment of associated autoimmune or inflammatory problems
- Referral for stem cell transplant in some severe forms
- Genetic counselling
When to seek medical help urgently
- High fever, especially in a child already known to have an immunodeficiency
- Breathing difficulty, drowsiness or poor feeding
- Any severe infection that is not improving with treatment
Questions parents often ask
My child catches colds often. Could it be immunodeficiency?
Healthy young children can have many colds a year, especially when they start daycare or school. Immunodeficiency is suspected when infections are severe, need hospital treatment, involve unusual germs, keep coming back in the same place, or come with poor growth.
Can my child receive vaccines?
It depends on the type of immunodeficiency. Inactivated vaccines are usually safe, though they may not work as well. Some live vaccines, such as BCG, oral polio, rotavirus, MMR and chickenpox vaccines, may be unsafe for certain children. Always tell the vaccinating doctor about the diagnosis.
Should brothers and sisters be vaccinated?
Yes, vaccinating family members helps protect the child. For some vaccines, such as oral polio, an alternative may be advised for siblings. Your doctor can guide you.
Is it inherited?
Most primary immunodeficiencies are caused by genetic changes. Genetic testing can confirm the diagnosis, guide treatment and help the family understand the chance of it occurring in future children.
Can my child lead a normal life?
With an accurate diagnosis and the right treatment, many children with immunodeficiency attend school, play and grow well. The outlook depends on the specific condition.
Related guides for parents
This page is general information and not a substitute for a consultation. Every child is different, and the right treatment depends on an individual assessment. Please do not start, stop or change any medicine without speaking to your child's doctor.