IgA nephropathy and IgA vasculitis are related autoimmune conditions that involve a part of the immune system called immunoglobulin A (IgA). While they share similarities, they affect the body in different ways and often show up differently over time.*

The Main Difference

• IgA nephropathy (Berger disease) affects only the kidneys. It can quietly damage the kidneys for years before symptoms appear.

• IgA vasculitis (formerly Henoch-Schönlein purpura) is a body-wide condition that affects small blood vessels, commonly involving the skin, joints, digestive system, and sometimes the kidneys.

How Symptoms Compare

IgA vasculitis usually appears suddenly and is easier to spot. People often develop a purple rash on the legs or buttocks, joint pain (especially in the knees and ankles), and abdominal pain that can sometimes include bleeding. Kidney symptoms—such as foamy or dark urine, swelling, or high blood pressure—may also occur.

IgA nephropathy, on the other hand, is often silent at first. Many people don’t notice symptoms until kidney damage is more advanced. When symptoms do appear, they are usually kidney-related, such as blood or protein in the urine, swelling in the feet or legs, or high blood pressure.

Who Is Most Affected

• IgA nephropathy most often begins in young adults, typically in their 20s or 30s.
• IgA vasculitis is more common in children under 10, though adults can develop it too.
• Both conditions are more common in people assigned male at birth.

Treatment Differences

Treatment depends on which condition you have and whether the kidneys are involved:

• IgA vasculitis without kidney involvement often improves with supportive care like fluids, pain relief, and monitoring.

• IgA nephropathy treatment focuses on protecting kidney function, often using blood pressure medications (such as ACE inhibitors), newer kidney-protective drugs, and sometimes immune-suppressing medications in more severe cases.

Shared Features

Despite their differences, both conditions:

• Are linked to autoimmune activity involving IgA
• Often develop after infections, especially respiratory infections
• Can lead to long-term kidney problems in some people
• May relapse or flare over time

About 1 in 5 people with IgA nephropathy develop kidney failure within 10 years, though outcomes vary widely. Kidney complications can also occur in IgA vasculitis, especially in adults.

Can You Have Both?

Yes. Some people with IgA vasculitis later develop kidney disease, and less commonly, people with IgA nephropathy may later show signs of vasculitis. Some experts believe these conditions may be different expressions of the same underlying disease process.

When to Seek Care

You should see a healthcare provider if you notice:

• Blood or foam in your urine
• New swelling in your legs or feet
• A sudden rash with joint or abdominal pain
• Signs of a flare if you’ve already been diagnosed

Early evaluation and monitoring are key—especially because kidney damage may not cause symptoms right away.

* Health (October, 2025). “What’s the Difference Between IgA Nephropathy and IgA Vasculitis?” health.com

Disclaimer:
The information provided by Responsum Health is for educational purposes only and does not replace professional medical advice. Always talk with your healthcare provider before making changes to your treatment or care. Responsum Health does not endorse specific treatments, providers, or products.