IgA nephropathy is a kidney disease that often starts quietly. Some people first notice tea-colored urine after a cold, sore throat, or stomach bug. Others feel completely well and only find out after a urine test shows blood or protein. That quiet start is exactly why the condition deserves careful follow-up: the main goal is to protect kidney function before lasting damage builds.
IgA nephropathy, also called Berger disease, affects the tiny filters in the kidneys. When those filters become inflamed, blood and protein leak into the urine. Over time, ongoing inflammation, high blood pressure, and protein loss strain the kidneys and raise the risk of chronic kidney disease.
The useful part is that IgA nephropathy is not a “wait and see” diagnosis. Doctors track urine protein, blood pressure, kidney function, and biopsy findings to estimate risk and choose a treatment plan. Kidney protection usually starts with proven supportive care, then adds specialist medicines when protein levels or kidney risk stay high.
Table of Contents
- What IgA Nephropathy Is
- Symptoms and Warning Signs
- How Doctors Diagnose IgA Nephropathy
- What Test Results Say About Kidney Risk
- The Core Kidney Protection Plan
- Medicines and Specialist Treatments
- Daily Living, Monitoring, and Common Mistakes
- When to Seek Help Quickly
What IgA Nephropathy Is
IgA nephropathy happens when immune proteins called immunoglobulin A, or IgA, collect in the kidney filters. These filters are called glomeruli. Their job is to keep blood cells and important proteins in the bloodstream while removing extra fluid and waste into urine.
In IgA nephropathy, IgA-containing immune complexes settle in the glomeruli and trigger inflammation. The filters become irritated and leaky. Blood leaks first in many cases, which is why microscopic blood in urine is a common early clue. Protein leakage matters even more for long-term risk because persistent protein in urine shows that the filters are under stress.
IgA is a normal part of the immune system, especially around the nose, throat, gut, and airways. The problem in IgA nephropathy is not simply “too much IgA.” The immune system makes an abnormal form of IgA that is more likely to form clumps. Those clumps travel through the blood and lodge in the kidneys.
This condition is usually long term. Some people have mild disease that stays stable for years. Others develop rising protein in urine, lower estimated glomerular filtration rate, high blood pressure, and kidney scarring. The course is easier to influence when the disease is found early and protein leakage is reduced.
IgA nephropathy is a form of glomerulonephritis, which means inflammation of the kidney filters. A broader explanation of filter inflammation is helpful if your doctor also uses terms like nephritic syndrome, crescents, or immune-complex disease; these fit under the larger topic of glomerulonephritis symptoms and testing.
Primary and secondary IgA nephropathy
Most people with IgA nephropathy have primary IgA nephropathy, meaning the kidney disease is the main condition. Secondary IgA deposits happen alongside another illness, such as some liver diseases, infections, inflammatory bowel disease, or immune conditions. The distinction matters because treatment needs to address the underlying driver when IgA kidney injury is part of a broader problem.
A kidney biopsy helps separate IgA nephropathy from other kidney diseases that also cause blood and protein in urine. Blood IgA levels alone do not diagnose it. A person with normal blood IgA still has biopsy-proven IgA nephropathy, and a person with high IgA does not automatically have kidney disease.
Symptoms and Warning Signs
The most recognizable symptom is urine that turns cola, tea, pink, or red, often during or soon after an upper respiratory infection. This pattern is different from many other kidney conditions because the urine color change often appears close to the illness, not weeks later.
Many people never see visible blood. Instead, a routine urine test shows microscopic blood, meaning blood cells are present but the urine looks normal. Protein leakage also starts silently. Over time, higher protein levels lead to foamy urine, swelling, and higher blood pressure.
Common signs include:
- Visible blood in urine, especially after a cold, sore throat, or stomach illness
- Microscopic blood found on urinalysis
- Foamy urine from protein leakage
- Swelling around the eyes, ankles, feet, or hands
- High blood pressure
- Fatigue when kidney function falls or anemia develops
- Lower urine output during more serious kidney injury
Blood in urine deserves proper evaluation, even when it comes and goes. Exercise, stones, infections, and bladder problems also cause blood, so the pattern needs testing rather than guesswork. A practical guide to blood in urine red flags explains when visible blood needs urgent care.
Foam is less specific. A few bubbles after a fast stream are common. Thick foam that repeatedly sits on the water, especially with swelling or high blood pressure, is more concerning. Persistent foam should lead to urine protein testing, not home interpretation. For a deeper look at this symptom, see foamy urine and protein testing.
Symptoms that suggest kidney stress is increasing
IgA nephropathy becomes more concerning when urine protein rises, blood pressure climbs, or kidney function drops. These changes do not always create obvious symptoms. That is why follow-up testing matters even when a person feels well.
Swelling around the eyes in the morning, tighter shoes by evening, new headaches with high blood pressure, or a sudden drop in urine amount needs medical attention. These signs suggest the kidneys are struggling with fluid balance, filtration, or both.
What IgA nephropathy does not usually feel like
IgA nephropathy usually does not cause sharp kidney stone-type pain. It also does not usually cause burning when peeing, fever, or strong urgency unless another problem, such as a urinary tract infection, is present. Back pain alone is not enough to identify kidney inflammation.
The key clue is the combination of urine abnormalities, blood pressure, kidney function, and sometimes swelling. Symptoms guide testing, but lab results guide risk.
How Doctors Diagnose IgA Nephropathy
A confirmed diagnosis requires a kidney biopsy. Urine and blood tests show that kidney filters are leaking or kidney function is changing, but they do not prove that IgA deposits are the cause. The biopsy shows IgA deposits in the kidney tissue and allows the pathologist to look for inflammation and scarring.
The usual workup starts with simple tests:
- Urinalysis checks for blood, protein, casts, and other urine findings.
- Urine protein measurement estimates how much protein is leaking, often with a urine protein-to-creatinine ratio or albumin-to-creatinine ratio.
- Blood creatinine and eGFR estimate kidney filtering ability.
- Blood pressure measurement shows one of the most important treatable risk factors.
- Additional blood tests rule out other causes, such as lupus, infections, complement disorders, or other immune kidney diseases.
- Kidney biopsy confirms the diagnosis and shows the pattern of injury.
A biopsy is not ordered for every trace of blood in urine. Doctors weigh the full picture: how much protein is present, whether eGFR is reduced, whether blood pressure is high, whether urine findings persist, and whether another cause is likely. The threshold for biopsy is lower when protein is clearly elevated or kidney function is changing.
A detailed explanation of the procedure is available in this guide to why kidney biopsy is done. In practical terms, the biopsy is usually performed with imaging guidance. A small sample of kidney tissue is taken with a needle, then examined with special staining and microscopy.
Why urine protein is measured more than once
Protein in urine fluctuates. Exercise, fever, dehydration, infection, and recent illness change results. Doctors often repeat testing or use a first-morning urine sample to get a cleaner picture. A single abnormal result matters, but a pattern over time matters more.
The amount of protein loss is one of the clearest signals of long-term risk. Persistent protein leakage means the kidney filters remain under pressure. Lowering that protein level is a major treatment target.
The topic overlaps with general proteinuria evaluation, covered in protein in urine causes and treatment. In IgA nephropathy, protein is not just a lab abnormality; it is a treatment guide.
What the biopsy report means
Biopsy reports often include the Oxford MEST-C score. This scoring system describes patterns seen under the microscope:
| Term | What it describes | Why it matters |
|---|---|---|
| M | Mesangial cell increase | Shows activity in the central part of the filter |
| E | Endocapillary inflammation | Suggests active inflammation inside filter loops |
| S | Segmental scarring | Shows partial scarring in some filters |
| T | Tubular atrophy and interstitial fibrosis | Reflects chronic kidney scarring and strongly affects prognosis |
| C | Crescents | Signals more aggressive injury when extensive or paired with fast eGFR decline |
The score does not make treatment decisions by itself. Doctors combine it with protein level, eGFR, age, blood pressure, and the speed of change. A biopsy with little scarring and low protein carries a different outlook from a biopsy with chronic scarring, high protein, and falling eGFR.
What Test Results Say About Kidney Risk
The most useful risk markers are protein in urine, eGFR trend, blood pressure, and biopsy scarring. A person with stable eGFR, low protein, and controlled blood pressure often follows a much safer path than someone with persistent high protein and declining kidney function.
Urine blood is important for diagnosis, but protein level is more closely tied to future kidney damage. Blood in urine that flares after infections looks alarming, but ongoing protein leakage is the result doctors work hardest to reduce.
eGFR estimates how well the kidneys filter. A single eGFR result needs context because hydration, muscle mass, recent illness, and lab variation affect the number. The trend is more useful. A steady eGFR over several years is reassuring. A downward slope, especially with rising urine protein, needs action.
A clear explanation of eGFR is available in this guide to low eGFR and kidney function. For IgA nephropathy, the main question is not only “What is my eGFR today?” but “Is it stable, and is my protein level low enough to protect it?”
Protein targets in plain language
Nephrologists often aim to reduce protein loss as much as safely possible. Lower is better, especially when kidney function is still good enough to preserve. In current specialist care, a urine protein goal below 0.5 grams per day is often used, with even lower levels preferred when achievable.
The exact measurement format varies. Your report might show:
- 24-hour urine protein in grams per day
- Urine protein-to-creatinine ratio
- Urine albumin-to-creatinine ratio
- Dipstick protein, such as trace, 1+, 2+, or 3+
Dipsticks are useful for screening, but ratios or timed collections are better for decisions. A dipstick result also changes with urine concentration. Dark, concentrated urine makes protein look stronger; very dilute urine makes it look weaker.
Blood pressure is a kidney result, not only a heart result
High blood pressure pushes extra force through already inflamed filters. That pressure worsens protein leakage and scarring. In IgA nephropathy, blood pressure control is one of the strongest kidney-protection steps.
Home readings often give a better picture than one clinic reading. A proper cuff size, seated rest, and repeated measurements matter. Bring your home log to appointments so your clinician sees the pattern, not one number taken during stress or pain.
The kidney-blood pressure connection is covered in more detail in high blood pressure and kidney disease.
The Core Kidney Protection Plan
The foundation of IgA nephropathy care is supportive kidney protection. That phrase sounds mild, but it is not passive care. It means lowering the pressure and protein leak inside the kidney filters every day, while avoiding extra injuries that speed scarring.
The core plan usually includes blood pressure control, protein reduction, sodium reduction, careful medication choices, healthy weight management, and regular monitoring. These steps remain important even when newer IgA-specific medicines are added.
Control blood pressure and reduce protein leakage
ACE inhibitors and ARBs are commonly used because they lower blood pressure and reduce pressure inside the kidney filters. Examples include lisinopril, enalapril, losartan, valsartan, and irbesartan. These medicines often lower urine protein even when blood pressure is not extremely high.
They require lab monitoring. Creatinine and potassium often change after starting or increasing the dose. A small creatinine rise is expected in some people because the medicine changes kidney blood-flow pressure. A large rise or high potassium needs prompt adjustment.
For more context, see ACE inhibitors for kidney protection and ARBs and kidney monitoring.
Lower sodium in a way that actually works
Sodium reduction improves blood pressure control and helps kidney-protective medicines work better. The biggest sources are usually not the salt shaker. They are bread, deli meats, canned soups, frozen meals, restaurant food, sauces, pickles, chips, and seasoning blends.
A practical target is to build meals around fresh or minimally processed foods and read labels for sodium per serving. A meal with 900 milligrams of sodium is already high for someone trying to protect kidney function. Sauces and packaged sides often add more sodium than the main protein.
Avoid common kidney stressors
Nonsteroidal anti-inflammatory drugs, such as ibuprofen and naproxen, are risky for people with kidney disease, especially during dehydration, illness, or ACE inhibitor/ARB use. Occasional use still deserves clinician guidance. Acetaminophen is often preferred for pain or fever when appropriate, but dose limits still matter.
Other kidney stressors include dehydration from vomiting or diarrhea, contrast dye in certain imaging tests, unreviewed supplements, and high-dose vitamin C or herbal products marketed for “kidney cleansing.” A useful safety rule is simple: tell every clinician you have IgA nephropathy before new medicines, imaging tests, or supplements.
Medicines and Specialist Treatments
Treatment choices depend on risk. Someone with low protein, normal eGFR, and normal blood pressure usually needs monitoring and supportive care. Someone with persistent protein despite optimized care needs a specialist discussion about additional therapy.
Current treatment has moved beyond a single steroid-or-no-steroid decision. Nephrologists now consider several treatment categories, including RAS blockade, SGLT2 inhibitors, targeted-release budesonide, endothelin pathway treatment, systemic steroids in selected cases, and clinical trials for immune or complement pathways.
SGLT2 inhibitors, such as dapagliflozin or empagliflozin, started as diabetes medicines but are now used for kidney protection in many people with chronic kidney disease. They reduce stress inside the filters and slow kidney function loss in proteinuric kidney disease. They require attention to dehydration risk, genital infections, sick-day rules, and eGFR thresholds. A broader explanation is available in SGLT2 inhibitors and kidney disease.
Targeted-release budesonide
Targeted-release budesonide is designed to act in the gut immune tissue involved in abnormal IgA production. It is not the same as taking standard prednisone. Because it is formulated for local release, it aims to reduce immune activity with less whole-body steroid exposure, though steroid-type side effects still occur.
Doctors consider it for adults with primary IgA nephropathy who remain at higher risk, especially when proteinuria stays elevated despite optimized supportive care. Side effects include acne, swelling, higher blood pressure, mood changes, weight gain, and changes in blood sugar in some patients.
Sparsentan and endothelin pathway treatment
Sparsentan blocks both the angiotensin receptor and endothelin receptor pathways. Endothelin contributes to blood vessel narrowing, inflammation, and scarring in the kidneys. This treatment is used to reduce proteinuria in selected adults with IgA nephropathy.
Because sparsentan affects blood pressure, kidney blood flow, potassium, liver safety monitoring, and pregnancy risk, it requires careful prescribing rules. It also replaces, rather than simply adds to, some standard RAS-blocking medicines because of overlapping effects.
Systemic steroids and immunosuppression
Systemic corticosteroids are reserved for selected higher-risk cases because they carry real risks: infection, weight gain, mood changes, high blood sugar, bone loss, cataracts, and blood pressure worsening. The decision is different for a person with rapidly progressive kidney inflammation than for someone with stable kidney function and modest proteinuria.
Other immune medicines are used only in specific situations. For example, rapidly progressive disease with crescents and fast eGFR loss needs urgent specialist management. Secondary IgA disease needs treatment of the underlying condition. Children, pregnancy, advanced CKD, and severe infections all change the risk-benefit calculation.
Daily Living, Monitoring, and Common Mistakes
Living with IgA nephropathy means tracking a few high-value signals instead of reacting to every symptom. The most useful routine numbers are blood pressure, urine protein, eGFR, creatinine, potassium, and sometimes cholesterol, albumin, and hemoglobin.
Monitoring schedules vary by risk. Stable, low-risk disease might be checked every few months. Higher-risk disease, medicine changes, pregnancy planning, or falling eGFR needs closer follow-up. After starting an ACE inhibitor, ARB, sparsentan, diuretic, or SGLT2 inhibitor, labs are usually checked soon enough to catch potassium or creatinine changes.
Food choices that support kidney protection
The most reliable diet step is sodium reduction. Protein intake also matters, but the answer is not “no protein.” Very high-protein diets increase kidney workload and often raise sodium intake through processed meats, protein bars, powders, and restaurant meals. A moderate protein plan is safer for most people with CKD risk.
A kidney-conscious plate usually includes vegetables and fruits matched to your potassium needs, whole grains or lower-sodium starches, and moderate portions of protein such as fish, poultry, eggs, beans, tofu, or lean meat. Potassium and phosphorus limits are not automatic in early IgA nephropathy. They become more important when eGFR falls or lab results show high levels.
For a practical overview, see CKD diet basics. The right diet depends on labs, not fear-based food lists.
Exercise, illness, and hydration
Regular activity supports blood pressure, weight, insulin sensitivity, and heart health. Walking, cycling, swimming, resistance training, and mobility work are usually reasonable when kidney function is stable. Heavy exercise sometimes causes temporary blood or protein on urine testing, so tell your doctor if a urine sample was taken after intense training.
During fever, vomiting, diarrhea, or poor fluid intake, kidney-protective medicines sometimes need temporary adjustment. Many clinics provide “sick day” instructions for ACE inhibitors, ARBs, diuretics, SGLT2 inhibitors, and similar medicines. Do not stop long-term medicines without a plan, but do ask your nephrology team what to do during dehydration or infection.
Common mistakes to avoid
The biggest mistake is assuming “no symptoms” means “no activity.” IgA nephropathy often changes silently. Skipping urine protein checks removes one of the best early warning signs.
Other common mistakes include:
- Treating visible blood as harmless because it happened before
- Focusing only on eGFR and ignoring urine protein
- Taking ibuprofen or naproxen during illness or dehydration
- Starting supplements without checking kidney safety
- Following extreme low-protein or high-protein diets without lab guidance
- Missing blood tests after medication changes
- Measuring blood pressure only at appointments
A simple home system works best: keep a blood pressure log, save lab reports, know your latest urine protein number, and bring questions to nephrology visits.
When to Seek Help Quickly
Some changes need same-day advice or urgent care. IgA nephropathy is usually monitored over time, but sudden kidney stress needs fast attention.
Seek urgent medical help for:
- Very low urine output or no urine
- Severe swelling with shortness of breath
- Chest pain, confusion, fainting, or severe weakness
- Very high blood pressure, especially with headache, vision changes, chest pain, or breathlessness
- Visible blood in urine with clots or inability to pee
- Fever, flank pain, and urinary symptoms suggesting kidney infection
- Rapid weight gain from fluid retention
- Vomiting or diarrhea when you take kidney-active medicines
Contact your nephrology team promptly if urine protein rises, eGFR drops, potassium is high, swelling appears, blood pressure becomes harder to control, or visible blood lasts beyond the infection that triggered it.
People with confirmed IgA nephropathy usually benefit from nephrology follow-up, even when disease seems mild. A nephrologist helps decide biopsy timing, protein targets, medicine choices, and monitoring frequency. This guide to when to see a nephrologist explains referral situations that overlap with IgA nephropathy.
The practical goal is not to chase every lab number with alarm. It is to spot the changes that predict kidney damage early enough to act. For most patients, that means keeping protein low, blood pressure controlled, medications monitored, and follow-up consistent.
References
- KDIGO 2025 Clinical Practice Guideline for the Management of Immunoglobulin A Nephropathy (IgAN) and Immunoglobulin A Vasculitis (IgAV) 2025 (Guideline)
- Contemporary review of IgA nephropathy 2024 (Review)
- An Update on Current Therapeutic Options in IgA Nephropathy 2024 (Review)
- Systematic Review of the Oxford Classification of IgA Nephropathy: Reproducibility and Prognostic Value 2023 (Systematic Review)
- Efficacy and safety of sparsentan versus irbesartan in patients with IgA nephropathy (PROTECT): 2-year results from a randomised, active-controlled, phase 3 trial 2023 (RCT)
- 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 2023 (RCT)
Disclaimer
This article is for education about IgA nephropathy and kidney protection. It does not diagnose your condition, interpret your biopsy, or replace care from a nephrologist. Treatment choices for IgA nephropathy depend on urine protein, eGFR trend, biopsy findings, blood pressure, pregnancy plans, infection risk, and medication safety monitoring.
