What is IgA nephropathy (Berger’s disease)?

It is a kidney disease in which the antibody IgA builds up in the kidney’s filters (glomeruli), causing inflammation that can gradually damage them and leak blood and protein into the urine. It is one of the most common forms of glomerulonephritis.

Why is it relevant to people in Singapore?

IgA nephropathy is more common in East Asian populations than in many Western ones, and glomerulonephritis is the second most common cause of kidney failure in Singapore after diabetes — so it is an important cause of kidney disease locally.

What is the classic symptom?

Episodes of visible blood in the urine (pink, red or cola-coloured), often during or right after a respiratory infection such as a cold or sore throat. Many people, though, have no symptoms and are found through a routine urine test.

Urine and blood tests raise the suspicion, but a kidney biopsy is needed to confirm it by showing IgA deposits in the glomeruli and assessing the degree of kidney damage.

There is no cure, but it can be managed. Controlling blood pressure and reducing urine protein — mainly with ACE inhibitors or ARBs — plus reducing salt and regular monitoring can slow the disease; higher-risk cases may need immunosuppression or newer agents.

IgA Nephropathy: Symptoms, Diagnosis & Treatment (Singapore)

Written & reviewed by the BestDoctors.sg editorial team · Last updated 1 Sep 2026 · General information, not medical advice

Quick answer. IgA nephropathy (Berger’s disease) is a kidney disease in which deposits of the antibody IgA build up in the kidney’s tiny filters (glomeruli), causing inflammation that can damage them over time. It is one of the most common forms of glomerulonephritis and is relatively more common in East Asian populations – relevant to Singapore. Many people have no early symptoms and it is found on a urine test; a classic feature is visible blood in the urine, often during or just after a cold or other respiratory infection. There is no cure, but controlling blood pressure and protein leak – mainly with ACE inhibitors or ARBs – slows the disease.

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IgA nephropathy varies enormously – from a mild, stable finding to a slowly progressive disease. Because it is often silent, a simple urine test is what usually brings it to light.

What it is

IgA (immunoglobulin A) is a normal antibody the body makes to defend the lining of the airways and gut against infection. In IgA nephropathy, an abnormal form of this antibody clumps together and lodges in the glomeruli – the millions of microscopic filtering units inside each kidney. The immune system treats these deposits as foreign, triggering inflammation in the filters. Over time this inflammation can scar the glomeruli, so that they begin to leak blood and protein into the urine and gradually filter the blood less efficiently. It is a form of glomerulonephritis, meaning inflammation of the glomeruli, and is one of the most common primary types worldwide. The name Berger’s disease comes from the doctor who first described the pattern of IgA deposits under the microscope.

Why it is relevant in Singapore

It is one of the most common types of primary glomerulonephritis worldwide, and rates are highest in East Asia, making it particularly relevant to Singapore’s population. Locally, glomerulonephritis overall is a leading cause of kidney failure, second after diabetes. In Singapore, a first clue often comes from a routine urine test at a GP clinic, polyclinic, workplace health screening or insurance medical, after which a nephrologist (kidney specialist) usually leads confirmation and long-term care.

Symptoms

Many people have no symptoms for years, and the condition is picked up only when a urine test shows blood or protein that should not be there. When symptoms do appear, the classic one is episodes of visible blood in the urine – urine that looks pink, red or cola-coloured – often appearing during or within a day or two of a respiratory infection such as a cold, sore throat or flu. These episodes may settle on their own and then recur with the next infection. Other possible features include:

Foamy or bubbly urine, a sign that protein is leaking into it.
Blood found only on testing (microscopic haematuria), with nothing visible to the eye.
High blood pressure, which may be the first thing detected.
Swelling (oedema) of the ankles, feet, hands or around the eyes, usually only when protein loss is heavy or kidney function has fallen.
Tiredness or a general feeling of being unwell if kidney function is reduced.

Causes

The exact trigger is not fully understood. The problem lies with an abnormal, poorly processed form of IgA that the body produces; these molecules stick together and settle in the glomeruli. Infections of the airways or gut often seem to set off flares, which is why visible blood in the urine so commonly follows a cold or sore throat – the immune system ramps up IgA production, and more of the abnormal antibody reaches the kidneys. In most people IgA nephropathy is a primary condition, meaning it arises on its own. Less commonly, a similar pattern of IgA deposits can occur alongside other conditions, such as certain liver or bowel diseases and some infections. It is not caused by diet or by anything a person has done, and it is not contagious.

Who is at risk

IgA nephropathy can affect anyone but is more common in some groups:

Young and middle-aged adults – it is frequently diagnosed in the teens to thirties, though it can appear at any age.
People of Asian descent – it is notably more common in East Asian and Singaporean populations than in many other parts of the world.
Men – in many populations it is diagnosed somewhat more often in males.
Family history – most cases are not inherited, but a small number run in families, so a relative with the condition or with unexplained kidney disease can raise the possibility.

How it is diagnosed

Diagnosis usually starts when a urine test shows blood, protein, or both. A doctor will typically arrange:

Urine tests to measure how much blood and protein are present and to estimate the amount of protein leaking each day.
Blood tests, including kidney function tests and eGFR, to gauge how well the kidneys are filtering.
Blood pressure checks, since raised pressure is common and important to control.

These tests raise the suspicion, but a kidney biopsy is what confirms the diagnosis. In this procedure a nephrologist takes a tiny sample of kidney tissue with a fine needle, usually under local anaesthetic and ultrasound guidance, so it can be examined under a microscope. The biopsy shows the characteristic IgA deposits in the glomeruli and reveals how much inflammation and scarring is present – information that guides treatment and gives a sense of the likely course.

Course and complications

The outlook is very variable, which is one of the defining features of this condition. Many people have a mild, stable form that never significantly affects their health and needs only monitoring. Others slowly progress over many years towards reduced kidney function and, in some, chronic kidney disease or eventual kidney failure requiring dialysis or a transplant. Features that tend to signal a higher risk of progression include persistently high levels of protein in the urine, high blood pressure that is hard to control, and more scarring seen on the biopsy. High blood pressure is both a common complication and a driver of further kidney damage, so keeping it well controlled is central to protecting the kidneys over time.

Treatment

There is no cure, so treatment aims to slow damage and protect kidney function over the long term. The main approaches are:

Controlling blood pressure and reducing protein leak. Medicines from the ACE inhibitor or ARB (angiotensin receptor blocker) classes are the mainstay: they both lower blood pressure and reduce the amount of protein lost in the urine, which helps preserve kidney function. Newer classes of kidney-protective medicine may also be used in selected cases.
Lifestyle and salt reduction. Cutting down on salt helps control blood pressure and protein loss. Not smoking, keeping to a healthy weight, and staying active all support kidney and heart health.
Immune-modulating treatment in selected cases. For people with a higher risk of progression – for example heavy, persistent protein loss despite the measures above – a nephrologist may consider treatments that dampen the immune response, such as steroids or other immune-modulating medicines. These carry their own risks and benefits and are used selectively.
Regular monitoring. Ongoing checks of urine protein, kidney function and blood pressure are essential to catch any progression early and adjust treatment.

The right combination depends on the individual, and a nephrologist can assess which approach fits a person’s biopsy findings, protein levels and overall health. Medicine classes are described here in general terms; specific drugs and doses are decisions for the treating doctor.

Living with it

Because IgA nephropathy is usually a long-term condition, day-to-day management matters as much as any one treatment. Helpful steps include:

Keeping monitoring appointments so that changes in urine protein or kidney function are picked up early.
Controlling blood pressure, including home monitoring if a doctor advises it.
Reducing salt in the diet – a common challenge with hawker and processed foods – and following any dietary guidance for kidney disease where relevant.
Not smoking, and being cautious with over-the-counter painkillers such as anti-inflammatories, which can affect the kidneys; check with a doctor or pharmacist.
Taking medication consistently, as ACE inhibitors and ARBs work best when taken regularly over the long term.

Reliable local information is available through HealthHub and the National Kidney Foundation Singapore, and a GP or polyclinic can help coordinate care alongside a nephrologist.

When to see a doctor

See a doctor if you notice blood in your urine, persistently foamy urine, or if a urine test has flagged blood or protein – especially if these recur. New or poorly controlled high blood pressure, or unexplained swelling of the ankles or around the eyes, also warrant assessment. A GP or nephrologist can arrange the right urine and blood tests and, where needed, a biopsy.

Red flags – seek urgent care. Go to A&E or call 995 if you develop severe symptoms such as passing very little or no urine, marked breathlessness, chest pain, severe swelling, or confusion, as these can point to a serious drop in kidney function or dangerously high blood pressure.

Related kidney & urinary conditions

Sources

NIDDK (US NIH) — IgA nephropathy: definition, symptoms, biopsy, ACE/ARB treatment, progression.
Cleveland Clinic — IgA nephropathy (Berger disease): mechanism, haematuria after infection, foamy urine, biopsy.
National Kidney Foundation (US) — diagnosis requires biopsy; ACE inhibitors/ARBs reduce protein; no cure.
NKF Singapore — glomerulonephritis: local context; second most common cause of kidney failure after diabetes.

General information only. This guide is general information about a kidney or urinary condition and is not a diagnosis or personalised medical advice. See a doctor — a GP, urologist or nephrologist — for assessment, tests and treatment. Go to A&E if you suddenly cannot pass urine and have a painful, full bladder, or if you have severe flank pain with fever.

IgA Nephropathy (Berger’s Disease) in Singapore