IgA is a protein, called an antibody, that helps the body fight infections. IgA nephropathy occurs when too much of this protein is deposited in the kidneys. IgA builds up inside the small blood vessels of the kidney. Structures in the kidney called glomeruli become inflamed and damaged.

The disorder can appear suddenly (acute), or get worse slowly over many years (chronic glomerulonephritis).

Risk factors include:

• A personal or family history of IgA nephropathy or Henoch-Schönlein purpura, a form of vasculitis that affects many parts of the body
• White or Asian ethnicity

IgA nephropathy can occur in people of all ages, but it most often affects males in their teens to late 30s.

There may be no symptoms for many years.

When there are symptoms, they may include:

• Bloody urine that starts during or soon after a respiratory infection
• Repeated episodes of dark or bloody urine
• Swelling of the hands and feet
• Symptoms of chronic kidney disease

IgA nephropathy is most often discovered when a person with no other symptoms of kidney problems has one or more episodes of dark or bloody urine.

There are no specific changes seen during a physical examination. Sometimes, the blood pressure may be high or there may be swelling in parts of the body.

Tests include:

• Blood urea nitrogen (BUN) test to measure kidney function
• Creatinine blood test to measure kidney function
• Kidney biopsy to confirm the diagnosis
• Urinalysis

The goal of treatment is to relieve symptoms and prevent or delay chronic renal failure.

The treatment may include:

• Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) to control high blood pressure and swelling (edema)
• Corticosteroids, other medicines that suppress the immune system
• Fish oil
• Medicines to lower cholesterol

Salt and fluid intakes may be restricted to control swelling. A low-to-moderate protein diet may be recommended in some cases.

Eventually, many people must be treated for chronic kidney disease and may need dialysis.

IgA nephropathy gets worse slowly. In many cases, it does not get worse at all. Your condition is more likely to get worse if you have:

• High blood pressure
• Large amounts of protein in the urine
• Increased BUN or creatinine levels

Contact your health care provider if you have bloody urine or if you are producing less urine than usual.

Nephropathy - IgA; Berger disease

Floege J, Barratt J, Zhang H. Immunoglobulin A nephropathy and IgA vasculitis (Henoch-Schönlein purpura). In: Johnson RJ, Floege J, Tonelli M, eds. Comprehensive Clinical Nephrology. 7th ed. Philadelphia, PA: Elsevier; 2024:chap 24.

Saha MK, Pendergraft WF, Jennette JC, Falk RJ. Primary glomerular disease. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 31.

Updated by: Walead Latif, MD, Nephrologist and Clinical Associate Professor, Rutgers Medical School, Newark, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.