What is IgA nephropathy?

The kidneys contain about a million microscopic filtering units called nephrons. Inside each nephron is a cluster of tiny blood vessels known as a glomerulus. These filters allow wastes and extra fluid to leave the bloodstream while normally keeping blood cells and useful proteins inside.

In IgA nephropathy, deposits containing an abnormal form of immunoglobulin A, or IgA, accumulate in the glomeruli. The immune system reacts to these deposits, causing inflammation. Repeated or persistent inflammation may damage the filtering barrier and gradually replace healthy tissue with scar tissue.

What does IgA normally do?

IgA is an antibody that helps protect surfaces exposed to the outside world, particularly the respiratory and digestive tracts. It is found in mucus, saliva, tears, and other secretions. In ordinary circumstances, it is one of the immune system’s useful security guards.

In IgA nephropathy, some IgA1 antibodies have an unusual sugar structure. The body may recognize these molecules as abnormal and produce additional antibodies against them. The resulting immune complexes can circulate through the blood and become trapped in the kidneys. In other words, the security team accidentally creates a paperwork crisis in the filtration department.

IgA nephropathy symptoms

IgA nephropathy often causes no noticeable symptoms during its early stages. Microscopic blood or protein may be discovered during a physical examination, employment screening, pregnancy visit, sports checkup, or investigation of high blood pressure.

Blood in the urine

Hematuria, meaning blood in the urine, is a classic sign. The blood may be visible, turning urine pink, red, tea-colored, or cola-colored. Episodes frequently appear during or shortly after a respiratory infection, such as a cold or sore throat. Visible hematuria can also occur after gastrointestinal infections or strenuous exercise.

Other people have microscopic hematuria, which cannot be seen but appears on a urine test. Blood in the urine has many possible causes, including infection, kidney stones, urinary tract disorders, and certain cancers, so it should never be diagnosed by color chart alone.

Protein in the urine

Damaged glomeruli may allow albumin and other proteins to leak into the urine. Larger amounts of protein can make urine unusually foamy or frothy. However, bubbles may also result from a forceful urine stream or cleaning products in the toilet. Laboratory testing is far more reliable than bathroom detective work.

Swelling and high blood pressure

As the kidneys lose their ability to balance salt and fluid, swelling may develop around the ankles, lower legs, hands, or eyes. Some people gain weight quickly because of retained fluid. Kidney damage can also raise blood pressure, and high blood pressure can then cause additional kidney damage. It is an unpleasant feedback loop rather than a productive team-building exercise.

Symptoms of more advanced kidney disease

When kidney function declines substantially, symptoms may include fatigue, nausea, poor appetite, itching, muscle cramps, difficulty concentrating, changes in urination, or shortness of breath. These symptoms are not specific to IgA nephropathy, but they require medical assessment when they are persistent or worsening.

When to seek urgent medical attention

Prompt care is important for severe swelling, breathing difficulty, very low urine output, confusion, chest pain, a major increase in blood pressure, or visible blood accompanied by clots, intense pain, fever, or weakness. A sudden decline in kidney function is uncommon but can occur.

What causes IgA nephropathy?

Researchers do not know why one person develops IgA nephropathy while another does not. Current evidence points to a combination of immune-system abnormalities, inherited susceptibility, and environmental influences.

The four-hit explanation

Scientists often describe the disease using a “four-hit” model:

1. The immune system produces increased amounts of galactose-deficient IgA1, an unusually structured antibody.
2. Other antibodies recognize this IgA1 as abnormal.
3. The antibodies join together and form circulating immune complexes.
4. Those complexes lodge in the glomeruli, activate inflammatory pathways, and damage kidney tissue.

This model explains why IgA nephropathy is considered an autoimmune kidney disease rather than an infection. A cold may trigger visible urinary changes, but the cold virus itself is not settling into the kidneys and building a tiny vacation home.

Genetic and environmental influences

The disease is more common in some families and populations, supporting a genetic component. It is frequently diagnosed between childhood and early middle age and is more commonly recognized in males. Rates also vary by ancestry and geographic region, although differences in screening and biopsy practices affect reported numbers.

Respiratory infections, digestive-tract immunity, the gut microbiome, and other environmental exposures may influence abnormal IgA production. Related IgA deposits can also occur with certain conditions, including chronic liver disease, inflammatory bowel disease, celiac disease, viral infections, autoimmune disorders, and IgA vasculitis. Doctors therefore assess whether the kidney findings represent primary IgA nephropathy or are associated with another illness.

IgA nephropathy is not contagious. It is not caused by poor hygiene, drinking too little water for one afternoon, or eating a protein-rich dinner. Diet may affect blood pressure and kidney workload after disease develops, but researchers have not found that a particular food causes the condition.

How IgA nephropathy is diagnosed

No single symptom can confirm IgA nephropathy. Evaluation usually begins with a medical history, blood pressure measurement, physical examination, urine testing, and blood tests.

Urine tests

A urinalysis can detect blood and protein. Doctors may then measure protein more precisely using a urine albumin-to-creatinine ratio, urine protein-to-creatinine ratio, or timed urine collection. Proteinuria is especially important because persistent higher levels are associated with a greater risk of disease progression.

Blood tests

Serum creatinine is used to calculate the estimated glomerular filtration rate, or eGFR. This estimate helps show how effectively the kidneys filter blood. Additional tests may check electrolytes, albumin, cholesterol, immune markers, infections, or possible secondary causes.

Kidney biopsy

A kidney biopsy is required to confirm IgA nephropathy. During the procedure, a clinician typically uses imaging guidance to remove a small sample of kidney tissue with a needle. A pathologist examines the sample for IgA deposits, inflammation, and scarring.

The biopsy can also be assigned an Oxford MEST-C score. This scoring system describes several microscopic features that may help estimate risk when combined with proteinuria, blood pressure, eGFR, age, and other clinical information. A biopsy result is not a crystal ball, but it gives the nephrology team much more than a blurry weather forecast.

IgA nephropathy treatment

There is no universal treatment plan. Therapy depends on protein levels in the urine, eGFR, blood pressure, biopsy findings, rate of change, age, other medical conditions, pregnancy considerations, medication risks, and personal preferences.

Modern management generally has two goals: reduce the ongoing immune processes that create harmful IgA complexes and protect the remaining nephrons from pressure, protein leakage, inflammation, and scarring.

Blood pressure and proteinuria control

ACE inhibitors and angiotensin receptor blockers, or ARBs, are commonly used to reduce blood pressure and urinary protein. They may protect the kidneys even when blood pressure is not dramatically elevated. Doses are usually adjusted according to blood pressure, kidney function, potassium levels, and tolerance.

SGLT2 inhibitors may also be recommended for eligible people with chronic kidney disease. Although originally developed for diabetes, these medicines can reduce pressure within the glomeruli and slow kidney function decline in many patients, including some who do not have diabetes.

Sparsentan, sold as Filspari, combines angiotensin-receptor and endothelin-receptor effects in one medicine. It replaces rather than accompanies an ACE inhibitor or ARB and requires specific safety monitoring. Other endothelin-pathway treatments, including atrasentan, may be options for selected adults.

Lifestyle measures that support kidney treatment

A kidney-protective plan commonly includes limiting sodium, maintaining a healthy weight, exercising regularly, avoiding tobacco, managing cholesterol, and taking medications consistently. A lower-sodium diet can reduce fluid retention and make blood pressure medicines more effective.

There is no single “IgA nephropathy diet” suitable for everyone. Protein, potassium, phosphorus, and fluid recommendations depend on kidney function and laboratory results. Extreme protein restriction can lead to malnutrition, while high-protein diets may be unhelpful for someone with significant kidney damage. A renal dietitian can turn a confusing stack of restrictions into meals that resemble actual food.

People with kidney disease should review over-the-counter medicines and supplements with their care team. Frequent use of nonsteroidal anti-inflammatory drugs, such as ibuprofen or naproxen, may further stress the kidneys in susceptible patients.

Corticosteroids and targeted-release budesonide

Corticosteroids reduce immune activity and inflammation, but systemic steroids can cause infection, elevated blood sugar, weight gain, bone loss, mood changes, and other significant complications. Current guidance favors careful patient selection and reduced-dose approaches when systemic glucocorticoids are considered.

Targeted-release budesonide, marketed in the United States as Tarpeyo, is designed to release medicine in part of the small intestine involved in IgA production. It can reduce proteinuria and slow kidney function loss in eligible adults, although it still has steroid-related risks and requires medical supervision.

Newer disease-targeted medicines

The treatment landscape has expanded rapidly. FDA-approved options for selected adults now include medicines that target the complement pathway, endothelin signaling, APRIL, or the BAFF/APRIL system. Examples include iptacopan, or Fabhalta; atrasentan, or Vanrafia; sibeprenlimab, or Voyxact; and atacicept-vymj, or Trutakna.

Trutakna received accelerated FDA approval on July 7, 2026, to reduce proteinuria in adults with primary IgA nephropathy at risk for progression. It targets both BAFF and APRIL, immune signals involved in B-cell survival and antibody production. The approval was based on reduced proteinuria, and an ongoing study must confirm whether it slows long-term kidney function decline.

Several newer drugs have accelerated approvals based on proteinuria reduction. This means they are approved options, but it does not mean every long-term question has already been answered. Medication selection requires discussion of expected benefits, infection risk, liver or laboratory monitoring, reproductive safety, vaccination needs, drug interactions, insurance coverage, and the strength of available kidney-outcome data.

Dialysis and kidney transplantation

If IgA nephropathy progresses to kidney failure, treatment may include hemodialysis, peritoneal dialysis, or kidney transplantation. Transplantation can restore kidney function and quality of life for eligible patients, although IgA deposits can recur in a transplanted kidney. Recurrence does not automatically mean the transplant will fail, and transplant teams monitor recipients closely.

Monitoring and prognosis

Follow-up usually focuses on urinary protein, eGFR, blood pressure, medication tolerance, potassium, and changes over time. A single test result is useful, but the trend is more informative. Kidney care is often less like taking one dramatic photograph and more like watching a long documentary in which every laboratory result gets a supporting role.

Persistent proteinuria, uncontrolled blood pressure, declining eGFR, and substantial scarring on biopsy are associated with a higher risk of progression. The 2025 KDIGO guideline identifies protein excretion of at least 0.5 gram per day as a level at which treatment or additional treatment should be considered. For people at risk, the guideline describes a treatment goal below 0.5 gram per day and ideally below 0.3 gram per day when achievable.

The National Institute of Diabetes and Digestive and Kidney Diseases estimates that about one in five people with IgA nephropathy develops kidney failure within 10 years of diagnosis. That statistic describes a population, not an individual destiny. Risk varies widely, and newer kidney-protective and disease-targeted treatments may improve future outcomes.

Regular care also includes managing cardiovascular risk, discussing pregnancy before conception, updating appropriate vaccinations, and addressing emotional well-being. Anxiety is understandable when a disease is chronic, unpredictable, and largely measured by numbers that arrive through a patient portal at 7:02 on a Friday evening.

Experience-based perspective: Living with IgA nephropathy

The following section summarizes commonly reported practical experiences and is not presented as one person’s medical story.

The diagnosis may feel strangely invisible

Many people describe a disconnect between feeling normal and being told that their kidneys are injured. There may be no pain, dramatic fatigue, or obvious physical limitation. Instead, the diagnosis arrives through a urine sample, a creatinine result, and eventually a biopsy report filled with unfamiliar terminology. That invisibility can make the condition difficult to explain. Friends may see someone who looks healthy, while that person is quietly calculating sodium, watching blood pressure, arranging laboratory visits, and wondering what the next eGFR result will show.

Urine changes can become emotionally loaded

After an episode of visible hematuria, an ordinary trip to the bathroom may become a source of apprehension. A respiratory infection that once meant tissues and soup may now prompt questions about kidney inflammation. It helps to ask the nephrology team for a written plan: when to report urine discoloration, when testing is needed, which symptoms are urgent, and whether medication instructions change during vomiting, diarrhea, fever, or dehydration. Clear guidance reduces the temptation to interpret every bubble as breaking medical news.

Laboratory trends matter more than one isolated number

Patients often learn a new vocabulary surprisingly quickly: eGFR, creatinine, UPCR, albumin, potassium, and MEST-C. Early on, a modest laboratory fluctuation may feel catastrophic. In reality, hydration, exercise, illness, medication changes, and normal testing variation can influence individual results. Nephrologists typically interpret patterns over time. Keeping a simple record of blood pressure, medication doses, urinary protein, and eGFR can make appointments more productive and help patients see the larger picture rather than emotionally wrestling with a single decimal point.

Treatment routines may require experimentation

Blood pressure medicines can cause dizziness, especially after dose changes. Sodium reduction may be easy at breakfast and surprisingly difficult when restaurant soup arrives carrying the salt content of a small inland sea. Steroid-based treatment can affect sleep, appetite, mood, glucose, or appearance. Newer therapies may involve injections, infection precautions, laboratory monitoring, specialty pharmacies, or insurance authorization. Reporting side effects early gives the care team a chance to adjust timing, dosage, supportive treatment, or the overall plan rather than allowing frustration to become nonadherence.

Work, exercise, and family life usually continue

Many people with stable IgA nephropathy continue working, studying, traveling, exercising, and raising families. The practical challenge is building kidney care into normal life without letting it become the entire plot. A portable medication list, home blood pressure monitor, refill reminders, lower-sodium travel snacks, and copies of recent laboratory results can reduce disruption. Pregnancy requires advance planning because some kidney medicines can harm a fetus and must be changed before conception. Discussing goals early is much safer than discovering a medication conflict after a positive test.

Emotional support is part of kidney care

Uncertainty can be one of the hardest parts of IgA nephropathy. Two people with the same diagnosis may follow very different paths, and online stories often feature the most frightening outcomes rather than the most typical ones. Reliable education, patient organizations, counseling, and peer support can reduce isolation. Useful questions for appointments include: What is my current level of risk? Which result matters most right now? What is the target for my urinary protein? What side effects should I report? What would cause us to change treatment? A clear plan does not eliminate uncertainty, but it gives uncertainty fewer rooms in which to rearrange the furniture.

Conclusion

IgA nephropathy is a chronic immune-mediated kidney disease caused by deposits of abnormal IgA-containing immune complexes in the glomeruli. It may produce visible or microscopic blood in the urine, proteinuria, swelling, and high blood pressure, but it can remain symptom-free for years.

A kidney biopsy confirms the diagnosis, while urinary protein, eGFR, blood pressure, and biopsy findings help guide treatment. Care usually begins with strong kidney protection through blood pressure control, reduced protein leakage, lower sodium intake, healthy daily habits, and regular monitoring. Selected patients may also benefit from corticosteroid-based treatment or newer medicines targeting specific disease pathways.

The growing number of therapies is encouraging, but successful care is not about collecting medications like trading cards. It is about matching the right treatment to the person’s risk, health, goals, and tolerance. With consistent follow-up and an individualized plan, many people can preserve kidney function and continue living full, active lives.