IgA Deficiency

IgA deficiency is a genetic condition that means your body doesn’t produce as many immunoglobulin A (IgA) antibodies as it should. Healthcare providers sometimes call it selective IgA deficiency, SIgAD or low IgA.

Immunoglobulins are proteins your immune system makes that protect your body against infections. IgA protects membranes throughout your body, including in your:

• Eyes
• Ears
• Mouth
• Airways
• Digestive system

SIgAD is a primary immunodeficiency disorder. Immunodeficiency disorders suppress your immune system and keep it from working properly. Your immune system is like your body’s built-in security system. Usually, it automatically detects substances that shouldn’t be in your body and sends out special cells to eliminate them. Immunodeficiency disorders weaken your body’s natural ability to defend itself. This can make you more likely to get sick and experience more severe symptoms and complications when you do.

If you have IgA deficiency, your B cells may not work correctly. B cells are a type of white blood cell that make infection-fighting proteins called antibodies.

The defective B cells might cause your body to make significantly less IgA than usual. Or none at all. Either way, your immune system won’t have all the tools it needs to fight infections.

It’s like putting together a puzzle that’s missing a handful of pieces. It might look mostly like the picture on the box when you’re done. But there are some areas not filled in. The missing pieces are your IgA antibodies.

Most people with selective IgA deficiency never experience symptoms or complications. You may not need to worry about it at all. A healthcare provider will help you understand the changes to your immune system and how they may affect you.

Symptoms of selective IgA deficiency

Getting sick more often and more severely than most people is the most common sign of SIgAD. But it doesn’t usually cause symptoms you can feel or notice.

You may be more likely to get sick from infections that IgA is supposed to fight, including:

• Eye infections, especially pink eye
• Ear infections
• Sinus infections
• Bronchitis
• Upper respiratory infections
• Pneumonia

You might also be more likely to have other health conditions that cause inflammation in your eyes, mouth, airways and digestive system, like:

• Asthma
• Allergies
• Chronic diarrhea
• Gastrointestinal diseases like ulcerative colitis or Crohn’s disease

IgA deficiency causes

Selective IgA deficiency is usually a genetic condition. That means biological parents pass the genetic changes that cause it to their children. It can be both an autosomal dominant and autosomal recessive condition.

Some people develop IgA deficiency as a side effect from certain medications, including:

• Immunosuppressants
• Penicillamine
• Phenytoin
• Sulfasalazine

Risk factors

Anyone can be born with IgA deficiency. But it’s almost always passed through biological families. You’re 50 times more likely to develop it if one of your biological parents has this condition.

People who are white or have European ethnic backgrounds have a higher risk. They’re more likely to have selective IgA deficiency in their biological family and pass it through generations. Experts estimate that around 1 in 500 people who are white have this disease.

What are the complications of selective IgA deficiency?

You probably won’t experience any complications from having IgA deficiency. Getting sick more often and more severely than usual is the most common issue.

Having this condition can make you more likely to develop some autoimmune diseases, including:

• Rheumatoid arthritis
• Lupus
• Celiac disease

Does low IgA cause fatigue?

Having this disease doesn’t cause fatigue, but it’s a common symptom of autoimmune diseases you might also have. Low IgA isn’t directly making you tired. But having an autoimmune condition might be.

Talk to your provider if you’re feeling tired or like you don’t have enough energy. They’ll help you find ways to manage the tiredness, no matter what’s causing it.

How do healthcare providers diagnose this condition?

A healthcare provider will diagnose selective IgA deficiency with a blood test. SIgAD is often diagnosed by accident when providers are checking for other conditions. The low levels of IgA may show up in one of your blood samples if your provider is testing you for another health condition.

If your provider thinks you might have IgA deficiency based on your health history, they might order the blood test that checks for it. Tell your provider if you know someone in your family has it.

Immunologists may order blood tests to evaluate someone who has frequent infections or signs of autoimmune diseases. You might also need to see a rheumatologist.

What are selective IgA deficiency treatments?

There’s no treatment for IgA deficiency itself. Your provider will suggest ways to manage any symptoms you experience. Or infections that make you sick.

You might need antibiotics to treat bacterial infections. Your provider may suggest IVIG infusions to strengthen your immune system’s natural defenses. You’ll also need medications or other treatments to manage any autoimmune diseases you may have.

How do you fix this disorder?

There’s no way to fix or correct SIgAD. Some children start producing correct amounts of IgA as they grow and develop. But there’s no way to guarantee this happens.

When should I see my healthcare provider?

Visit your healthcare provider if you feel like you get sick too often. Or if you experience symptoms you can’t explain.

Even if it feels like a small issue, you shouldn’t feel sick all the time. Talk to your provider if it seems like it takes longer than usual to recover after even minor illnesses.

What can I expect if I have IgA deficiency?

Most people with selective IgA deficiency don’t experience any complications. It’s the mildest form of immunodeficiency. But it can still impact your daily routine.

You might get sick more often than most people. And you might have to be more cautious about being around people who are sick. Make sure your loved ones know that you have a higher risk of getting sick than most people. They can help you stay healthy by letting you know when they’re sick and helping you avoid catching illnesses they have.