IgG4-Related Disease

Overview

IgG4-related disease is a chronic immune-mediated condition in which inflammation and scar-like (fibrous) tissue accumulate in one or more organs. It is named for a type of antibody called IgG4 that is often, though not always, raised in the blood and found in the affected tissues. The disease tends to cause firm swelling or mass-like lesions that can resemble cancer, infection, or other inflammatory conditions.

Almost any organ can be involved, including the pancreas, salivary and tear glands, lymph nodes, kidneys, lungs, and the tissue behind the abdomen. Because it can affect different organs and mimic other diseases, IgG4-related disease can be challenging to recognize. The good news is that it often responds well to treatments that calm the immune system, especially when caught before permanent organ damage occurs.

Symptoms

Symptoms depend on which organs are affected and often develop gradually. Common patterns include:

• Painless swelling of the salivary glands (in the cheeks) or tear glands (around the eyes)
• Swelling of lymph nodes
• Abdominal pain, jaundice, or pancreas problems when the pancreas or bile ducts are involved
• Kidney involvement, sometimes found on imaging or blood tests
• Breathing symptoms if the lungs are affected
• General symptoms such as weight loss and fatigue

Because the swellings can look like tumors, the condition is sometimes first suspected to be cancer. New jaundice, severe abdominal pain, or rapidly enlarging masses should be evaluated promptly.

Causes

The exact cause of IgG4-related disease is not fully understood. It is considered an immune-mediated condition, meaning the immune system drives the inflammation and fibrous tissue formation. Current understanding includes:

• Abnormal immune activity: Certain immune cells appear to drive the inflammation and scarring in affected organs.
• The IgG4 antibody: Often elevated and present in tissues, though its precise role is still being studied.
• Genetic and environmental factors: May contribute, but no single cause has been identified.

It is not contagious and is not a form of cancer, although it can closely mimic cancer.

Risk Factors

• Middle-aged and older adults are most commonly affected
• Men are affected somewhat more often than women for some forms
• A history of allergic conditions in some people
• No clear preventable risk factors are known

Diagnosis

Diagnosis combines clinical findings, imaging, blood tests, and, importantly, tissue examination:

• Blood tests: IgG4 levels are often raised, though normal levels do not rule out the disease.
• Imaging: CT, MRI, or other scans show organ swelling or masses and how widely organs are involved.
• Biopsy: Examining affected tissue under a microscope shows characteristic features and is key to confirming the diagnosis and excluding cancer.

Because it can mimic cancer and infection, careful evaluation by specialists is often needed.

Treatment

The goal of treatment is to reduce inflammation, shrink the swelling, and prevent permanent organ damage.

• Corticosteroids: Often the first treatment, frequently producing rapid improvement.
• Steroid-sparing and immune-targeting medications: Used to maintain control, reduce steroid side effects, or treat disease that returns.
• Monitoring: Regular follow-up with imaging and blood tests, since the disease can relapse.
• Treating complications: Procedures may be needed if, for example, a swollen area blocks a bile duct.

Many people respond well, especially when treated early, though relapses can occur and long-term follow-up is important.

Prevention

• There is no known way to prevent IgG4-related disease
• Early diagnosis and treatment can prevent lasting organ damage
• Keep regular follow-up appointments to catch relapses early
• Report new swellings or symptoms promptly so treatment can be adjusted

When to See a Doctor

See a doctor for persistent painless swelling of glands, lymph nodes, or other tissues, or for unexplained symptoms such as jaundice, abdominal pain, or weight loss. Seek prompt care for new jaundice, severe abdominal pain, or a rapidly growing mass, both to evaluate IgG4-related disease and to rule out other serious conditions such as cancer.

Related Topics

Frequently Asked Questions

References

1. National Institutes of Health (NIH). IgG4-related disease.
2. MedlinePlus, U.S. National Library of Medicine. IgG4-related disease.
3. American College of Rheumatology. IgG4-related disease.
4. Genetic and Rare Diseases Information Center (GARD). IgG4-related disease.