IgA Nephropathy (Berger Disease): Symptoms, Causes, and Treatment
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD. Last reviewed October 17, 2026. This content is for educational purposes and is not medical advice.
Quick Answer
IgA nephropathy, or Berger disease, is a kidney disease caused by the antibody IgA building up in the kidneys' tiny filters, called glomeruli. [1] [3] Symptoms include blood in the urine, foamy urine, swelling and high blood pressure. [1] [3] A kidney biopsy is the only way to confirm it. [1] [3] There is no cure, but medicines and lifestyle changes can slow the disease. [1] [3]
What the research says
A targeted-release budesonide slowed kidney function decline. In 364 adults with IgA nephropathy and persistent proteinuria, kidney function (eGFR) declined by 2.47 mL/min per 1.73 m² with Nefecon versus 7.52 with placebo over 2 years, a difference of 5.05 (Lafayette et al., Lancet, 2023). [6]
Sparsentan cut protein loss more than irbesartan. After 110 weeks in 404 patients, urine protein was 40% lower with sparsentan than with irbesartan, and the yearly eGFR decline was slower (2.7 versus 3.8 mL/min per 1.73 m² per year) (Rovin et al., Lancet, 2023). [7]
Iptacopan reduced proteinuria. At month 9 in the phase 3 trial (443 patients in the main population), the urine protein-to-creatinine ratio was 38.3% lower with iptacopan than with placebo, with no unexpected safety findings (Perkovic et al., N Engl J Med, 2025). [8]
What is IgA nephropathy?
IgA nephropathy (pronounced "nuh-FROP-uh-thee"), also known as Berger disease, is a kidney disease. [1] [3] It happens when a germ-fighting protein called immunoglobulin A (IgA) builds up in the kidneys. [1] [3] This buildup causes a type of swelling called inflammation that, over time, can make it harder for the kidneys to filter waste from the blood.
The disease usually gets worse slowly over years, but the course varies from person to person. Some people leak blood into their urine without having other problems. Others develop complications such as loss of kidney function or protein spilling into the urine. Still others develop kidney failure, which means the kidneys stop working well enough to filter the body's waste on their own.
There is no cure for IgA nephropathy, but medicines can slow how quickly it becomes worse. [1] [3] With treatment, some people reach remission, a state where the disease becomes not active. Keeping blood pressure under control and lowering cholesterol also slow the disease.
A typical first visit for suspected IgA nephropathy involves reviewing urine and blood test results with a doctor.
At a Glance: IgA Nephropathy in One Table
Fact | Detail |
Also called | |
What happens | |
How it starts | Often no symptoms for 10 years or more [3] |
Common signs | |
How it is confirmed | |
Cure | |
End goal of treatment | Delay or avoid dialysis or kidney transplant |
What are the symptoms of IgA nephropathy?
IgA nephropathy often causes no symptoms early on. [1] [3] You might not notice any health effects for 10 years or more [3]. Sometimes the disease is found only through routine medical tests that show protein and red blood cells in the urine under a microscope. [1] [3]
When symptoms do appear, they can include the following:
Symptom | What you may notice |
Dark urine | |
Visible blood | Blood can be seen in the urine |
Foamy urine | Protein leaking into the urine, called proteinuria |
Back pain | Pain on one or both sides of the back below the ribs |
Swelling | Swelling in the hands and feet, called edema [3] |
High blood pressure | New or hard-to-control blood pressure |
Fatigue | Weakness and tiredness [3] |
If the disease leads to kidney failure, symptoms may include rashes and itchy skin, muscle cramps, upset stomach and vomiting, less appetite, a metallic taste in the mouth, and confusion. Kidney failure is life-threatening without treatment, but dialysis or a kidney transplant can help people live for many more years.
When to see a doctor: Get a checkup if you notice blood in your urine, especially if it keeps happening or does not go away. Also see a doctor if you notice sudden swelling in your hands or feet. Many conditions can cause blood in the urine, but persistent bleeding can be a sign of a serious health problem and should never be ignored.
What causes IgA nephropathy?
To understand the cause, it helps to know how the kidneys work. The kidneys are two bean-shaped, fist-sized organs at the small of the back, one on each side of the spine. They remove waste and extra fluid from the blood through filtering units called nephrons. Each nephron contains a filter called a glomerulus made of tiny blood vessels called capillaries. When blood flows into a glomerulus, water, minerals, nutrients, and waste pass through the capillary walls, while large molecules such as proteins and red blood cells stay in the blood. The useful substances return to the bloodstream, and the waste becomes urine that flows to the bladder.
Immunoglobulin A (IgA) is a type of antibody. [1] [3] The immune system makes IgA to help attack germs and fight infections. In IgA nephropathy, this protein collects in the glomeruli instead. This causes inflammation and affects the filters' ability over time. [1] [3]
Healthy filters become inflamed when IgA proteins collect inside them, and damaged filters leak protein into the urine.
Researchers do not know exactly what causes IgA to build up in the kidneys [1] [3], but several factors may be linked with it:
Possible link | Explanation |
Genes | More common in some families and in certain ethnic groups, especially people of Asian and European descent [3] |
Liver diseases | Including cirrhosis (scarring of the liver) and chronic hepatitis B and C infections |
Celiac disease | A digestive condition triggered by eating gluten, a protein found in most grains |
Infections | Including HIV and some bacterial infections |
Who is most at risk?
Risk factor | What the evidence shows |
Sex | In North America and Western Europe, at least twice as many men as women are affected |
Ethnicity | More common in white people and people of Asian descent than in Black people |
Age | Most often develops between the mid-teens and mid-30s [3] |
Family history |
Can IgA nephropathy become life-threatening?
Yes, in its most serious form. The course varies from person to person: some people live with the disease for years with few or no problems, and many are never diagnosed. But the following complications can develop:
Complication | What happens |
High blood pressure | Kidney damage raises blood pressure, and high blood pressure damages the kidneys further, creating a cycle |
High cholesterol | Raises the risk of a heart attack |
Acute kidney failure | Waste products rise quickly in the blood; if function worsens very fast, it is called rapidly progressive glomerulonephritis |
Chronic kidney disease | Kidneys stop working over time, and dialysis or a kidney transplant becomes necessary [3] |
Nephrotic syndrome | A group of problems including high urine protein, low blood protein, high cholesterol and lipids, and swelling of the eyelids, feet, and stomach area |
The key takeaway: the main goal of treatment is to keep you from ever needing dialysis or a kidney transplant. But if your kidneys do stop working well enough on their own, either treatment can be lifesaving.
How is IgA nephropathy diagnosed?
IgA nephropathy is often discovered after you notice blood in your urine, or when a routine test shows protein or blood in the urine. [1] [3] Several exams help build the full picture.
Diagnostic test | What it does |
Urine tests | A lab checks a urine sample under a microscope to see how well the kidneys work and how much protein they are spilling; blood in the urine can hint at inflamed kidney filters |
Blood tests | May show higher levels of the waste product creatinine or the protein cystatin C [4] |
Kidney biopsy | |
Iothalamate clearance test | Uses a special contrast agent to track how well the kidneys filter waste |
How is IgA nephropathy treated?
There is no cure for IgA nephropathy [1] [3], and there is no sure way to predict how much the disease will affect your health over time. Some people need only medical tests to track whether the disease is getting worse. For others, medicines can slow the disease and help manage symptoms. [1]
Treatment | What it does |
Blood pressure drugs (ACE inhibitors and ARBs) | |
Immune-calming medicines (immunosuppressants) | Corticosteroids and other strong medicines that may keep the immune system from making the proteins that attack the filters; can cause serious side effects such as high blood pressure, high blood sugar, and greater infection risk, so a doctor helps you choose; many new treatments have been approved or are being tested in clinical trials |
Omega-3 fatty acids | Healthy fats that may curb inflammation in the filters without harmful side effects; ask your doctor about prescription fish oil supplements rather than off-the-shelf versions |
Cholesterol medicine | Controls high cholesterol and slows kidney damage |
Diuretics | Help control swelling in the hands and feet |
The main goal of treatment is to keep you from needing dialysis or a kidney transplant.
What can I do at home to protect my kidneys?
Everyday habits play a real role in slowing kidney damage:
Habit | Why it helps |
Lower your blood pressure | Slows kidney damage; limit sodium and fat, lose extra weight, exercise regularly, drink alcohol only in moderation, and take blood pressure medicines as prescribed |
Track blood pressure at home | Write down each reading and bring the record to checkups, if your health care team asks you to |
Eat less protein | May slow the disease and protect the kidneys; ask your doctor first whether you should cut back |
Home blood pressure tracking and a low-sodium diet are two of the most practical ways to protect the kidneys.
Is there a support network for people with IgA nephropathy?
Coping with severe forms of the disease can be challenging, but you do not have to do it alone. Talk with a member of your health care team if you have questions or need guidance. Support groups let you meet others who understand what you are going through. Ask your health care team about groups in your area, or contact the National Kidney Foundation to learn about NKF Peers, a program that connects kidney patients with trained mentors.
How do I prepare for my appointment?
You will likely start by seeing your primary doctor and may be referred to a nephrologist, a doctor trained to treat kidney disorders. Before your visit, ask the office whether you need to fast for a blood test. Prepare a list of your symptoms and when they began, all medicines you take (including doses, over-the-counter drugs, vitamins, herbs, and supplements), and the questions you want to ask. Ask a family member or friend to come along to help remember the information you receive.
Useful questions to ask include what tests you need, the best course of action, how long you will need medicines, whether diet and lifestyle changes can manage the disease, and how to manage any other health conditions alongside it. Expect your doctor to ask how often your symptoms happen, how severe they are, and what seems to make them better or worse.
Conclusion: what matters most about IgA nephropathy
IgA nephropathy is a silent disease for many people, sometimes showing no effects for a decade or more. That silence is exactly why blood in the urine and sudden swelling deserve attention, not dismissal. The diagnosis is confirmed with a single kidney biopsy, and while no cure exists, today's medicines and everyday habits can slow the disease significantly. Some people reach remission, and many avoid dialysis or a transplant for years.
Next steps: If you have noticed blood in your urine, foamy urine, or new swelling, talk with a doctor soon.
Frequently asked questions
Is IgA nephropathy the same as Berger disease?
Yes. IgA nephropathy and Berger disease are two names for the same kidney condition. [1] [3] It is caused by a germ-fighting antibody called immunoglobulin A building up in the tiny filters of the kidneys and causing inflammation over time. [1] [3]
Can IgA nephropathy be cured?
No cure exists, but medicines can slow how quickly the disease gets worse. [1] [3] Treatment aims for remission, a state in which the disease is not active, and for delaying or avoiding the need for dialysis or a kidney transplant.
Why does my urine look like cola or tea?
Cola- or tea-colored urine is caused by blood leaking into the urine, a hallmark sign of IgA nephropathy. [3] The color changes often show up after a cold, sore throat, or respiratory infection [1] [3] and should be checked by a doctor, especially if they recur.
How long does it take for IgA nephropathy to cause symptoms?
IgA nephropathy often causes no symptoms early on, and you may not notice any health effects for 10 years or more. [3] Sometimes the condition is discovered only through routine tests that find protein or red blood cells in the urine under a microscope. [1] [3]
What is the only way to confirm IgA nephropathy?
A kidney biopsy is the only definitive test. [1] [3] A special needle takes small pieces of kidney tissue that are examined under a microscope. Urine tests, blood tests, and imaging studies point toward the disease, but the biopsy confirms it.
Trusted External Resources
References
National Kidney Foundation. IgA Nephropathy (IgAN). National Kidney Foundation. Last updated August 6, 2026. https://www.kidney.org/kidney-topics/iga-nephropathy
National Institute of Diabetes and Digestive and Kidney Diseases. What is Kidney Failure? National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Last reviewed January 2018. https://www.niddk.nih.gov/health-information/kidney-disease/kidney-failure/what-is-kidney-failure
American Kidney Fund. IgA Nephropathy (IgAN). American Kidney Fund. Last updated August 19, 2026. https://www.kidneyfund.org/all-about-kidneys/other-kidney-diseases/iga-nephropathy
National Kidney Foundation. Cystatin C. National Kidney Foundation. Last updated July 26, 2023. https://www.kidney.org/kidney-topics/cystatin-c
Urology Care Foundation. Hematuria. Urology Care Foundation. Updated October 2025. https://www.urologyhealth.org/urology-a-z/h/hematuria
Lafayette R, Kristensen J, Stone A, et al. Efficacy and safety of a targeted-release formulation of budesonide in patients with primary IgA nephropathy (NefIgArd): 2-year results from a randomised phase 3 trial. Lancet. 2023;402(10405):859-870. PMID 37591292. https://doi.org/10.1016/S0140-6736(23)01554-4
Rovin BH, Barratt J, Heerspink HJL, et al. Efficacy and safety of sparsentan versus irbesartan in patients with IgA nephropathy (PROTECT): 2-year results from a randomised, active-controlled, phase 3 trial. Lancet. 2023;402(10417):2077-2090. PMID 37931634. https://doi.org/10.1016/S0140-6736(23)02302-4
Perkovic V, Barratt J, Rovin B, et al. Alternative Complement Pathway Inhibition with Iptacopan in IgA Nephropathy. N Engl J Med. 2025;392(6):531-543. PMID 39453772. https://doi.org/10.1056/NEJMoa2410316
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