Selective IgG Deficiency

What is Selective IgG Deficiency?

Selective IgG deficiency is a mild immune system condition where your body makes lower than normal levels of immunoglobulin G antibodies. IgG antibodies are proteins that help fight off bacteria and viruses. They make up about 75 percent of all antibodies in your bloodstream. When you have low IgG levels, your immune system has a harder time protecting you from infections.

This condition is less common than other types of antibody deficiencies. Most people with selective IgG deficiency live normal lives with only mild symptoms. Some people have no symptoms at all and only discover the condition through routine blood testing. The deficiency can affect one or more of the four IgG subclasses your body produces.

Unlike severe immune deficiencies, selective IgG deficiency usually does not cause life-threatening complications. Many people manage the condition well with preventive care and prompt treatment of infections. Understanding your IgG levels helps you and your doctor create a plan to keep your immune system working its best.

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Symptoms

Frequent respiratory infections like sinus infections, bronchitis, or pneumonia
Recurring ear infections, especially in children
Chronic cough that does not go away
Fatigue that persists even with adequate rest
Digestive issues including diarrhea or stomach upset
Skin infections that heal slowly or keep coming back
Allergies or asthma that seem harder to control

Many people with selective IgG deficiency have no symptoms, especially if the deficiency is mild. Others only notice they get sick slightly more often than friends or family. Symptoms typically appear in childhood but can develop at any age.

Causes and risk factors

The exact cause of selective IgG deficiency is not fully understood. In some cases, the condition runs in families and appears to have a genetic component. Your immune system may not produce enough IgG antibodies due to how your B cells, the immune cells that make antibodies, develop or function. Some people are born with the deficiency while others develop it later in life.

Certain medications like steroids or drugs that suppress the immune system can lower IgG levels temporarily. Chronic health conditions including kidney disease or intestinal disorders may also reduce IgG levels. In many cases, doctors cannot identify a specific cause. Children with selective IgG deficiency sometimes outgrow the condition as their immune systems mature.

How it's diagnosed

Doctors diagnose selective IgG deficiency through specialized blood tests that measure your immunoglobulin levels. A quantitative immunoglobulin test checks your total IgG along with other antibody types like IgA and IgM. If your IgG is low but other immunoglobulins are normal, your doctor may order additional tests to check the four IgG subclasses individually.

Your doctor will review your medical history and infection patterns before ordering immune testing. They may also check how well your immune system responds to vaccines, since people with IgG deficiency sometimes make fewer antibodies after vaccination. Talk to your doctor about specialized testing if you experience frequent or severe infections. They can refer you to an immunologist who specializes in immune system disorders.

Treatment options

Prompt treatment of bacterial infections with antibiotics to prevent complications
Preventive antibiotics for people who get frequent serious infections
Staying up to date on vaccines, including flu and pneumonia vaccines
Good hand washing and hygiene practices to reduce infection exposure
Eating a nutrient-dense diet with adequate protein, vitamins, and minerals
Getting enough sleep to support immune function, typically 7 to 9 hours nightly
Managing stress through relaxation techniques, exercise, or counseling
Avoiding smoking and secondhand smoke, which damages respiratory defenses
Immunoglobulin replacement therapy for severe cases with repeated serious infections

Frequently asked questions

Selective IgG deficiency affects only your IgG antibody levels while other antibody types remain normal. Other immune deficiencies may involve multiple antibody types or affect different parts of your immune system. Selective IgG deficiency is generally milder than combined immune deficiencies. Most people with this condition do not experience severe or life-threatening infections.

Some children with selective IgG deficiency outgrow the condition as their immune systems mature. This is more common when the deficiency is detected in early childhood. Adults rarely see spontaneous improvement, though symptoms may vary over time. Regular monitoring with blood tests helps track whether IgG levels change or remain stable.

Testing frequency depends on your symptoms and infection history. People with frequent infections may need testing every 6 to 12 months to monitor IgG levels. Those with mild or no symptoms might only need testing every few years. Your doctor will recommend a schedule based on your individual situation and how well you manage infections.

Most people with selective IgG deficiency do not need immunoglobulin replacement therapy. This treatment is reserved for people who have severe, repeated infections that do not respond to antibiotics. Your doctor will consider replacement therapy if you develop frequent pneumonia, chronic sinus disease, or other serious complications. The majority of patients manage well with preventive care and prompt infection treatment.

Yes, most people with selective IgG deficiency live completely normal lives. You may get respiratory infections slightly more often than others. Taking good care of your health, staying current on vaccines, and treating infections promptly helps prevent complications. Many people with mild deficiency never experience significant health problems.

Respiratory infections are the most common problem, including sinus infections, ear infections, and bronchitis. Some people develop recurring pneumonia or chronic lung inflammation. Skin infections and digestive tract infections occur less frequently. The infections are usually caused by bacteria that IgG antibodies normally help fight off.

Talk to your doctor about testing your children, especially if they have frequent infections. Selective IgG deficiency can run in families, though not everyone with a family history develops the condition. Testing is most helpful when children show symptoms like repeated respiratory infections or slow recovery from illness. Routine screening is not necessary for children without symptoms.

Some people with selective IgG deficiency make fewer antibodies after vaccination compared to people with normal IgG levels. Your doctor may test your antibody response after certain vaccines to see how well your immune system reacts. Despite potentially lower responses, vaccines are still important and recommended. They provide some protection even if antibody levels are not as high as usual.

Eating a balanced diet rich in fruits, vegetables, lean proteins, and whole grains supports immune health. Getting adequate sleep, managing stress, and exercising regularly all help your body fight infections. Avoiding smoking and limiting alcohol protects your respiratory system. Good hand hygiene and avoiding people who are sick reduces your infection exposure.

See your doctor early when you develop symptoms of a respiratory infection, especially fever, productive cough, or difficulty breathing. Prompt antibiotic treatment can prevent simple infections from becoming serious. Contact your doctor if you have infections that last longer than usual or keep coming back. Early intervention helps prevent complications like pneumonia or chronic sinus disease.