Iga Deficiency

Overview

IgA deficiency (doctors sometimes call it selective IgA deficiency) is a condition where your immune system makes too little of one type of antibody called immunoglobulin A, or IgA. Antibodies are protective proteins your body makes to fight off germs. IgA is the type that guards the moist surfaces of your body — the lining of your nose, throat, lungs and gut. When IgA is low, those surfaces have less protection, so some people pick up infections a bit more easily, especially in the ears, sinuses, chest and tummy. Many people with IgA deficiency never have any symptoms at all and only find out about it from a routine blood test.

Yes — it is the most common primary immune deficiency (an immune problem you are born with). Rates vary around the world: it is more common in people of European background and less common in people of East Asian and African background. Because so many people have no symptoms, the true number is likely higher than the number of diagnosed cases.

It can affect anyone at any age, but it is most often picked up in children and young adults. Some children are found to have low IgA when they are tested for repeated infections, and a number of them will see their levels return to normal as they grow. Adults are sometimes diagnosed when they are investigated for recurring sinus or chest infections, tummy problems, allergies or an autoimmune condition.

Symptoms

Common symptoms

• No symptoms at all — this is very common
• Frequent or long-lasting colds and sore throats
• Repeated sinus infections or ear infections
• Chest infections or bronchitis that keep coming back
• Stomach bugs, ongoing loose stools, or bloating, sometimes linked to a gut infection
• Allergies, hay fever, eczema or asthma
• Feeling more tired than usual during and after infections

Symptoms in children

• Frequent ear infections or 'glue ear' and repeated courses of treatment
• Colds and coughs that seem to last longer than other children's
• Stomach upsets or diarrhoea that come back
• Poor appetite or slower weight gain during a run of infections (check with your doctor)
• Many children have no symptoms at all and grow up perfectly well

Symptoms in older adults

• Infections that take longer to clear or need repeated treatment
• Chest infections that leave a lasting cough or breathlessness
• Being diagnosed alongside an autoimmune condition such as thyroid problems or coeliac disease
• Note: some adults first learn they have low IgA during tests for another reason

Causes

Main causes

• It is mainly caused by genetic factors — the tendency runs in families, and there is often a family history of IgA deficiency, other immune problems, allergies or autoimmune conditions.
• It happens because the immune system's antibody-making cells do not produce enough IgA, even though other antibodies are made normally.
• Sometimes low IgA is linked to a known genetic condition, such as one affecting the immune system or the chromosomes, and this is why your doctor may ask about your family and general health.
• Some medicines can lower IgA levels, and rarely it follows an infection or another illness. Your doctor will consider these possibilities.

Risk factors

• Having a close family member with IgA deficiency or another immune deficiency
• Having an autoimmune condition, such as coeliac disease, thyroid disease, rheumatoid arthritis or type 1 diabetes
• Having allergies, asthma or eczema
• Certain genetic conditions that affect the immune system or chromosomes
• Being of European ancestry (it is more common in this group)

When to see a doctor

See a doctor urgently if:

• You or your child have a fever with unusual drowsiness, confusion, fast breathing or blotchy skin
• A chest infection that is worsening despite rest, or you are coughing up blood
• You cannot keep fluids down, or you are passing very little urine
• You have swelling of the face, lips or throat, or trouble breathing — call your local emergency number straight away

Book a routine appointment if:

• You or your child keep getting infections of the ears, sinuses, chest or gut
• Infections seem to take much longer to clear than they used to
• You have ongoing loose stools, bloating, weight loss or poor appetite
• You have a family member with IgA deficiency and want to talk about your own risk
• You have been told you have low IgA and want to understand what it means for you
• You are planning a blood transfusion or blood product treatment — your team needs to know about your IgA level in advance

Diagnosis

IgA deficiency is usually found with a blood test. The test measures the amount of IgA in your blood alongside the other main antibodies, IgG and IgM. If IgA is very low while the others are normal, and you are past early childhood (levels are still changing in very young children), the diagnosis is usually made. Because the condition often runs in families, your doctor may suggest testing close relatives, especially if they also get frequent infections.

Tests that may be done

• A blood test measuring immunoglobulin levels — IgA, IgG and IgM
• Repeat testing a few months later, to make sure the low level is lasting rather than a temporary dip
• A blood count and general blood tests to look at your overall health
• Tests for coeliac disease, thyroid problems or other autoimmune conditions if you have symptoms
• A stool (poo) sample if you have ongoing diarrhoea, to look for gut infections
• A chest X-ray or breathing tests if you have had repeated chest infections
• A test for antibodies against IgA (anti-IgA antibodies) in some people, especially if a blood transfusion is planned

What to expect at your appointment

The first step is simple and quick: a blood sample from your arm. You may be asked to come back for a repeat test after a few months, because a single low reading is not always the whole story. Depending on your symptoms, your doctor may also check for related conditions such as allergies, coeliac disease or asthma. Expect a conversation about your infection history and your family's health. This is a friendly, step-by-step process — nothing about it is painful beyond the usual small needle prick.

Treatment

There is no cure for IgA deficiency, and most people do not need any ongoing treatment. The main approach is to treat infections promptly if they happen, keep an eye on related conditions such as allergies or autoimmune disease, and support your general health. Antibody replacement therapy, which some people with other immune deficiencies receive, is generally not used for IgA deficiency because it contains IgA and can cause reactions in people who make antibodies against it.

Self-care at home

• Wash your hands often, especially before eating and after using the toilet or being in crowded places
• Follow food safety basics — cook meat properly, wash produce, and be careful with unpasteurised foods, especially when travelling
• Keep up good sleep, regular movement, and a balanced diet to support your immune system
• Do not smoke, and avoid second-hand smoke, as it irritates the airways
• Keep a simple record of your infections (when, where, how long) so you can share it with your doctor
• Tell any doctor, dentist or nurse treating you about your IgA level, especially before any blood transfusion or blood product
• Ask your pharmacist before starting new medicines or supplements

Medical treatments

When an infection happens, your doctor will treat it in the usual way — this may include a course of antibiotics for a bacterial infection, inhalers for asthma, or other treatments for allergies and related conditions. Live vaccines are generally considered safe in IgA deficiency but your clinician will check whether any vaccine needs special timing. If you ever need a blood transfusion or blood product, your care team will take extra steps to choose a product that is safe for you. People with frequent chest infections may be referred to a lung or immunology specialist for a closer look.

When is surgery considered?

Surgery is not a treatment for IgA deficiency itself. Occasionally, surgery may be needed for a related problem, such as putting drainage tubes in the ears of a child with repeated ear infections, or treating sinus problems. Your surgical team should know about your IgA level beforehand so any blood products can be chosen carefully.

Living with this condition

For most people, IgA deficiency is a small part of daily life. You may simply be a bit more alert to infections and mention your IgA level when you see a new doctor. Some people find it helpful to keep a short note in their phone or wallet saying they have IgA deficiency, so that anyone treating them in an emergency knows to check blood products carefully.

Lifestyle tips

• Build hand-washing into your routine and teach children to do the same
• Stay active — regular moderate exercise supports your immune system and mood
• Eat a varied, balanced diet with plenty of fruit and vegetables
• Get enough sleep, and manage stress where you can
• Avoid smoking and smoky places
• Stay up to date with recommended vaccinations, checking with your clinician about any live vaccines
• Travel wisely — check food and water safety advice for your destination

Diet and exercise

There is no special diet for IgA deficiency, but a balanced, varied diet helps you stay well. If you also have coeliac disease or a food allergy, you will need to avoid certain foods — your doctor or a dietitian can guide you. Some people find that probiotics or fermented foods suit them, but check with your pharmacist or doctor first, and be careful with unpasteurised products. Exercise is encouraged: walking, cycling, swimming and other moderate activity are all good. Build up gradually if you have been unwell, and drink enough water.

Mental health and emotional wellbeing

Being told you have an immune condition can feel unsettling, and repeated infections can be tiring and frustrating — for parents of young children too. It is completely normal to feel anxious or worn down at times. Talk to your doctor about your worries; they can explain what is and is not a concern for you personally. If low mood, worry or stress is affecting your sleep, work or relationships, please reach out for mental health support. If you ever feel you might harm yourself, contact your local emergency number or a local crisis line straight away — help is available and you deserve it.

Prevention

No, IgA deficiency cannot be prevented — it is something you are born with, not something caused by anything you did or did not do. What you can do is reduce the chance of infections causing trouble, by keeping up good hygiene, staying vaccinated, and getting symptoms checked early.

Vaccines

Vaccination is an important part of staying well. Most routine vaccines are recommended and are considered safe for people with IgA deficiency. Because a small number of vaccines are 'live' (made with a weakened germ), your clinician will confirm which ones are right for you or your child and whether any timing matters. Keep a record of vaccinations and take it to appointments.

Screening programmes

There is no national screening programme for IgA deficiency. Testing is offered when someone has suggestive symptoms, a strong family history, or when it is needed before a blood transfusion. If a close relative is found to have IgA deficiency, it is reasonable to mention this to your own doctor so they can decide whether testing is worthwhile.

Complications

If left untreated

• More frequent or longer-lasting infections of the ears, sinuses, chest and gut
• Repeated chest infections can, over many years, cause damage to the airways (called bronchiectasis), which needs specialist care
• Some people develop an autoimmune condition such as coeliac disease, thyroid problems or rheumatoid arthritis
• A gut infection with a parasite (giardia) can become long-lasting and cause diarrhoea and weight loss
• A rare but important risk: a reaction to a blood transfusion or blood product, because some people with IgA deficiency make antibodies against IgA — this is why you should always tell your care team
• Some studies suggest a slightly higher chance of certain other conditions over a lifetime, which your doctor can discuss with you calmly and in context

Long-term outlook

The outlook is generally very good. Most people with IgA deficiency have a normal lifespan and a normal day-to-day life, and many have no symptoms at all. Some children see their IgA levels return to normal as they grow. If infections are frequent, a clear plan with your doctor — early treatment, monitoring and sometimes specialist input — keeps most problems manageable. Having IgA deficiency is not a reason to put your plans on hold.

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