Immunoglobulin A Nephropathy - Symptoms, Causes, Treatment & Prevention

📅 Updated: June 2026 ⏱ 6 min read ✅ Medically reviewed
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Immunoglobulin A Nephropathy (IgA Nephropathy) – What You Need to Know

Overview

Immunoglobulin A (IgA) nephropathy, also called Berger disease, is a chronic kidney disorder characterized by the buildup of IgA antibodies in the glomeruli – the tiny filtering units of the kidney. This deposition triggers inflammation, which can gradually scar the glomeruli, impairing the kidney’s ability to filter waste and excess fluid from the blood.

Who it affects: IgA nephropathy can develop at any age, but it most commonly appears in the late teens to early 30s. It is slightly more prevalent in males than females (approximately 60% vs. 40%).1 The disease occurs worldwide, with higher reported rates in East Asian populations (Japan, China, Korea) compared with North America and Europe.2

Prevalence: The exact global prevalence is uncertain because many cases remain undiagnosed. In Japan, kidney biopsies indicate an incidence of about 2–3 per 100,000 people per year, while in the United States the prevalence is estimated at 2–5 per 100,000 adults.3 Roughly 20% of patients progress to end‑stage renal disease (ESRD) within 20 years of diagnosis.4

Symptoms

Symptoms can be subtle at first and may vary from person to person. Common manifestations include:

  • Hematuria (blood in the urine): Often the earliest sign, described as “tea‑colored” or “cola‑colored” urine. It may appear during or after an upper‑respiratory infection.
  • Proteinuria (protein in the urine): Ranges from mild to nephrotic‑level (>3.5 g/day). Protein loss can cause swelling.
  • Edema (swelling): Usually in the legs, ankles, or around the eyes, especially after prolonged standing.
  • Hypertension (high blood pressure): Frequently present early and can accelerate kidney damage.
  • Reduced urine output: May signal worsening kidney function.
  • Flank pain: Rare, but some patients report dull discomfort in the sides.
  • Fatigue and malaise: Result from anemia and toxin buildup.
  • Foamy urine: A sign of significant proteinuria.

In many individuals, the disease is discovered incidentally during routine urinalysis for another reason.

Causes and Risk Factors

IgA nephropathy is considered an autoimmune disease, but the precise trigger is not fully understood.

Pathophysiology

  • Aberrant IgA1 production: The body makes IgA1 molecules with abnormal hinge‑region sugars, making them prone to forming immune complexes.
  • Immune complex deposition: These complexes lodge in the glomerular mesangium, activating complement (especially the alternative pathway) and causing inflammation.
  • Genetic predisposition: Certain HLA haplotypes (e.g., HLA‑DR4) and genetic variants at the CFHR1/CFHR3 locus increase susceptibility.5

Risk Factors

  • Family history of IgA nephropathy or related kidney disease.
  • North‑East Asian ancestry (higher incidence).
  • Male gender.
  • Recurrent mucosal infections (e.g., sinusitis, tonsillitis) that stimulate IgA production.
  • Co‑existing liver disease (cirrhosis) – may alter IgA clearance.
  • Smoking (linked to faster progression).

Diagnosis

Because early symptoms overlap with many other kidney disorders, a systematic approach is required.

Initial Evaluation

  • Medical history & physical exam: Focus on urine changes, blood pressure, family kidney disease, and recent infections.
  • Urinalysis: Detects hematuria, proteinuria, and casts.
  • Blood tests: Serum creatinine, estimated glomerular filtration rate (eGFR), complete blood count, complement levels (C3, C4), and IgA serum concentration.
  • Blood pressure measurement: Hypertension is both a symptom and a prognostic factor.

Confirmatory Tests

  • Kidney biopsy (gold standard): Light microscopy shows mesangial proliferation; immunofluorescence reveals dominant IgA deposition in the mesangium; electron microscopy confirms electron‑dense deposits.
  • Genetic testing (optional): May be offered in familial cases or research settings.
  • Imaging: Renal ultrasound is used to evaluate kidney size and rule out obstruction, but it does not diagnose IgA nephropathy.

Treatment Options

Therapy aims to slow progression, control blood pressure, and reduce protein loss. Treatment is individualized based on proteinuria level, eGFR, and blood pressure.

Medications

  • Renin‑angiotensin system blockers: ACE inhibitors (e.g., lisinopril) or ARBs (e.g., losartan) are first‑line for proteinuria reduction and blood‑pressure control. They can lower proteinuria by 30–50% and improve renal survival.6
  • Immunosuppressive agents:
    • Corticosteroids: Short‑course prednisone may be used for patients with proteinuria >1 g/day and preserved eGFR.
    • Mycophenolate mofetil (MMF): Helpful in some patients with persistent proteinuria despite ACE/ARB therapy.
    • Cyclophosphamide: Reserved for rapidly progressive disease (crescentic IgA nephropathy).
    • Tonsillectomy: In Japan, tonsil removal combined with steroid pulse therapy has shown modest benefit, though data are mixed.
  • Fish‑oil (omega‑3 fatty acids): May modestly reduce proteinuria and inflammation; recommended dose 2–4 g/day of EPA/DHA combined.
  • Blood‑pressure‑lowering agents: Calcium‑channel blockers, diuretics, or beta‑blockers may be added if target BP <130/80 mm Hg is not reached.

Procedures & Advanced Therapies

  • Plasmapheresis: Considered only for patients with severe, rapidly progressive disease; evidence is limited.
  • Dialysis: Initiated when eGFR falls <15 mL/min/1.73 mÂČ or when uremic symptoms develop.
  • Kidney transplantation: Offers the best long‑term renal replacement; recurrence of IgA nephropathy in the graft occurs in ~30% of cases but rarely leads to graft loss within the first 5 years.7

Lifestyle Modifications

  • Maintain blood pressure <130/80 mm Hg.
  • Limit sodium intake to <2 g per day.
  • Adopt a low‑protein diet (0.8 g/kg body weight) if proteinuria is high, under dietitian guidance.
  • Engage in regular aerobic exercise (150 min/week) to improve cardiovascular health.
  • Avoid smoking and excessive alcohol.
  • Stay up‑to‑date with vaccinations (influenza, pneumococcal, hepatitis B) to reduce infection‑related flares.

Living with Immunoglobulin A Nephropathy

Managing a chronic kidney condition involves daily choices that support kidney health and overall well‑being.

Practical Tips

  • Monitor blood pressure at home: Use a validated cuff and keep a log for your clinician.
  • Regular urine checks: Home dip‑stick kits can detect new or worsening proteinuria/hematuria.
  • Follow-up schedule: See a nephrologist at least twice yearly; more often if kidney function declines.
  • Nutrition:
    • Emphasize fruits, vegetables, whole grains, and healthy fats.
    • Limit processed foods high in phosphorus additives.
    • Consult a renal dietitian for individualized meal plans.
  • Medication adherence: Use pill organizers or smartphone reminders.
  • Stay active socially and mentally: Chronic illness can impact mood; consider support groups or counseling.

Prevention

Because the underlying genetic and immunologic factors cannot be changed, prevention focuses on modifiable risks:

  • Prompt treatment of upper‑respiratory infections and chronic sinusitis.
  • Vaccinations to avoid infections that may trigger IgA production.
  • Smoking cessation.
  • Blood‑pressure control even before a diagnosis (screen high‑risk individuals).
  • Maintaining a healthy weight and avoiding excessive protein or salt intake.

Complications

If left untreated or poorly controlled, IgA nephropathy can lead to:

  • Progressive CKD → End‑Stage Renal Disease (ESRD): Requires dialysis or transplantation.
  • Hypertensive heart disease: Left ventricular hypertrophy, heart failure.
  • Cardiovascular events: Increased risk of myocardial infarction and stroke.
  • Anemia: Due to reduced erythropoietin production.
  • Bone‑mineral disorders: Hyperphosphatemia, secondary hyperparathyroidism.
  • Infections: Immunosuppressive therapy raises susceptibility.

When to Seek Emergency Care

Immediate medical attention is required if you experience any of the following:

  • Sudden, severe swelling of the legs, face, or abdomen.
  • Rapid rise in blood pressure (≄180/120 mm Hg) with headache, vision changes, or chest pain.
  • Sharp flank pain accompanied by blood in the urine.
  • Reduced urine output to less than 200 mL in 24 hours.
  • Persistent vomiting, confusion, or signs of uremia (metallic taste, severe itching, nausea).

Call emergency services (911 in the U.S.) or go to the nearest emergency department.

References:

  1. Mayo Clinic. “IgA nephropathy.” Mayo Clinic Proceedings. 2022.
  2. World Health Organization. Global Kidney Health Atlas. 2021.
  3. Japan Society of Nephrology. “Epidemiology of IgA Nephropathy.” Kidney International. 2020.
  4. National Kidney Foundation. “Kidney Disease Outcomes in IgA Nephropathy.” 2023.
  5. Gharavi AG, et al. “Genetic susceptibility to IgA nephropathy.” Nat Rev Nephrol. 2021.
  6. Chiang J, et al. “Renin‑angiotensin system blockade in IgA nephropathy.” Cleveland Clinic Journal of Medicine. 2022.
  7. Hoesli M, et al. “Recurrence of IgA nephropathy after kidney transplantation.” Transplantation. 2020.
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Important: The information provided on this page is for general informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

If you think you may have a medical emergency, call your doctor, go to the emergency department, or call 911 immediately.

📚 Medical References