Condition Deep-Dives 10 min read·Updated 22 July 2026 Clinician-reviewed

IgA Nephropathy (Berger's Disease)

A UK Consultant Nephrologist's plain-English guide to IgA nephropathy — what it is, how it's diagnosed, the new treatments now available, and what to expect long-term.

  • Clinically Reviewed
  • NHS & NICE Aligned
  • UK Evidence-Based
  • Last Reviewed 22 July 2026

Professor Mohammed Mahdi Althaf

Consultant Nephrologist & Acute Physician

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Professor Mohammed Mahdi Althaf

MD, MSc, PgDip (Clin Ed), FRCP, FHEA, FASN

Consultant Nephrologist & Acute Physician · GMC 7216325

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Direct answer

IgA nephropathy is the commonest glomerulonephritis worldwide. Diagnosed by biopsy. Treatment combines ACE/ARB, SGLT2 inhibitors, and now Kinpeygo or sparsentan for proteinuria. Prognosis has improved dramatically — most patients stabilise with modern care.

Key recommendation: Commonest glomerulonephritis worldwide.

Quick answer

✓ Best choices

  • Plant proteins: beans, lentils, tofu, tempeh, chickpeas
  • Vegetables, fruit and whole grains
  • Oily fish 1–2 times a week
  • Olive oil as the main cooking fat

✓ Foods to limit

  • Added salt (≤ 6 g/day)
  • Processed meats and high-additive ready meals
  • Excess animal protein at every meal

Key takeaway

IgA nephropathy is the commonest glomerulonephritis worldwide. Diagnosed by biopsy. Treatment combines ACE/ARB, SGLT2 inhibitors, and now Kinpeygo or sparsentan for proteinuria. Prognosis has improved dramatically — most patients stabilise with modern care.

Who should be cautious

People on dialysis, post-transplant, pregnant or breastfeeding, or taking prescription medication — confirm with your renal team before changes.

IgA Nephropathy (Berger's Disease)

What is IgA nephropathy?

IgA nephropathy (IgAN), also called Berger's disease after the French nephrologist who described it in 1968, is the most common primary glomerulonephritis in the world.

What Happens

  • Your immune system makes a slightly abnormal form of IgA antibody (galactose-deficient IgA1)
  • These antibodies clump together and deposit in the mesangium (the supporting structure) of the kidney's filters (glomeruli)
  • The deposits trigger inflammation, leaking blood and protein into urine
  • Over years, this causes scarring and CKD

How Common

  • Diagnosed in ~25 per million UK adults per year
  • Likely 10× more common — many go undiagnosed
  • Twice as common in men
  • Often appears age 15–35
  • Higher in East Asian populations

Symptoms and how it's found

Presentations

1. VISIBLE BLOOD IN URINE WITH INFECTIONS (most classic):

  • Coca-cola or tea-coloured urine 24–48h after sore throat, cold, GI bug, or vigorous exercise
  • Lasts a few days, resolves
  • 'Synpharyngitic haematuria' — happens WITH the infection (unlike post-strep GN which happens 2 weeks later)

2. INCIDENTAL FINDING (now most common):

  • Blood (and sometimes protein) on routine urine dip — life insurance, antenatal, occupational health
  • Microscopic haematuria persisting between episodes

3. NEPHROTIC SYNDROME (~5%):

  • Heavy proteinuria, leg swelling, low albumin

4. Already Advanced CKD

  • High BP, fatigue, raised creatinine — biopsy reveals IgAN

5. Rarely Acute Kidney Injury

  • 'Crescentic IgAN' — needs urgent immunosuppression

Kidney Vitality is a daily multivitamin developed by a UK Consultant Nephrologist using renal nutrition principles. It contains no added potassium, magnesium, phosphorus or iron, and no herbal blends. See the formulation.

Diagnosis — the biopsy

There is NO blood test that diagnoses IgA nephropathy. The only certain diagnosis is a kidney biopsy.

Before Biopsy

  • Urine ACR (proteinuria)
  • Urine microscopy (dysmorphic red cells, casts)
  • Blood pressure
  • eGFR
  • Tests to exclude lupus (ANA, complement), vasculitis (ANCA), HIV, hepatitis, infection

Biopsy Findings

  • Light microscopy: mesangial proliferation
  • Immunofluorescence: DOMINANT IgA deposits — diagnostic
  • Electron microscopy: mesangial dense deposits

MEST-C SCORE — predicts prognosis:

  • M — mesangial hypercellularity
  • E — endocapillary proliferation
  • S — segmental sclerosis
  • T — tubular atrophy/fibrosis
  • C — crescents

This is reported by the renal histopathologist and guides treatment intensity.

Modern treatment

STEP 1 — SUPPORTIVE (everyone):

  • ACE inhibitor or ARB titrated to maximum tolerated dose
  • BP target < 125/75 mmHg (if proteinuria > 1 g/day)
  • SGLT2 inhibitor (dapagliflozin or empagliflozin) — proven benefit
  • Salt restriction < 5 g/day
  • Statin if appropriate
  • Treat any tonsillitis promptly; tonsillectomy still controversial
  • Stop smoking; control weight; treat OSA
  • 3–6 months on this before stepping up

STEP 2 — IF PROTEINURIA REMAINS > 0.75–1 g/day:

  • TARGETED-RELEASE BUDESONIDE (Kinpeygo/Tarpeyo) — releases steroid in distal ileum where IgA is made; UK NICE approved 2023
  • SPARSENTAN — dual endothelin/angiotensin blocker; UK NICE approved 2024
  • These can be combined with SGLT2 inhibitor for additive effect

STEP 3 — RAPIDLY PROGRESSIVE / CRESCENTIC:

  • High-dose IV methylprednisolone
  • Cyclophosphamide or rituximab
  • Specialist nephrologist supervision

STEP 4 — KIDNEY FAILURE:

  • Dialysis options
  • Transplantation — IgAN can recur in transplant (~30%) but usually mild; outcomes generally good

What to expect long-term

Outlook

  • 20-30% reach kidney failure over 20-30 years if untreated
  • Modern treatment cuts this substantially
  • Median time to kidney failure: ~25 years from diagnosis (untreated cohorts)

PROGNOSTIC FACTORS — WORSE:

  • Proteinuria > 1 g/day persistently
  • High BP
  • Reduced eGFR at diagnosis
  • T (tubular atrophy/fibrosis) and C (crescents) on biopsy
  • Male sex, smoking

PROGNOSTIC FACTORS — BETTER:

  • Isolated microscopic haematuria only
  • Normal eGFR, normal BP
  • Proteinuria < 0.5 g/day
  • No crescents on biopsy

Monitoring

  • 3-monthly: BP, urine ACR, creatinine
  • 6-monthly with stable disease
  • Lifelong — never discharge

LIVING WITH IgAN:

  • Aerobic exercise is safe and encouraged
  • Pregnancy is usually safe with stable function; close monitoring needed
  • Avoid NSAIDs
  • Annual flu, COVID, 5-yearly pneumococcal vaccines
  • Genetic counselling not usually needed (sporadic in most)
Protein in Urine (Proteinuria)
Related reading: Protein in Urine (Proteinuria).

Key practical tips

Designed for quick scanning — what to order, what to avoid, sensible portions, common mistakes.

  • Take prescribed ACE inhibitor / ARB / SGLT2 inhibitor consistently — diet works alongside, not instead
  • Monitor BP at home weekly
  • Review urine ACR with your team to track progress

Clinical guidance

TL;DR summary

IgA nephropathy is the commonest glomerulonephritis worldwide. Diagnosed by biopsy. Treatment combines ACE/ARB, SGLT2 inhibitors, and now Kinpeygo or sparsentan for proteinuria. Prognosis has improved dramatically — most patients stabilise with modern care.

Key takeaways
  • Commonest glomerulonephritis worldwide.
  • Often presents with blood in urine after a cold.
  • Diagnosed only by kidney biopsy.
  • New drugs (Kinpeygo, sparsentan) halve progression.
  • Tight BP < 125/75 + ACE/ARB + SGLT2 inhibitor = backbone.
Kidney Diet & Nutrition Considerations

When protein is leaking into the urine, the goal is to protect the remaining kidney function. Dietary protein should be sensible — neither very high nor unnecessarily low — and a Mediterranean-style plate with reduced salt supports both blood pressure and albuminuria reduction alongside ACE inhibitors, ARBs or SGLT2 inhibitors.

Foods to prioritise

  • Plant proteins: beans, lentils, tofu, tempeh, chickpeas
  • Vegetables, fruit and whole grains
  • Oily fish 1–2 times a week
  • Olive oil as the main cooking fat

Foods to limit

  • Added salt (≤ 6 g/day)
  • Processed meats and high-additive ready meals
  • Excess animal protein at every meal

Potassium, phosphate and protein needs vary between individuals — please confirm personal targets with your renal team or dietitian. Browse the Kidney Diet Hub for more guides in this cluster.

Frequently asked questions

What is IgA nephropathy?

IgA nephropathy (Berger's disease) is the world's commonest primary glomerulonephritis. Abnormal IgA antibodies deposit in the kidney filters (glomeruli), causing inflammation, blood and protein in urine, and over years, scarring. It's diagnosed by kidney biopsy.

What are the symptoms?

Many people have no symptoms — picked up on a routine urine dip showing blood. Classic presentation is visible blood in urine 24-48 hours after a sore throat or chest infection ('synpharyngitic haematuria'). Some present with high BP, ankle swelling, or already advanced CKD.

Will I need dialysis?

Around 30-40% reach kidney failure over 20-30 years if untreated. New treatments (sparsentan, targeted-release budesonide/Kinpeygo, SGLT2 inhibitors) are changing this — many patients now stabilise long-term. Prognosis depends on proteinuria, BP control and biopsy findings (MEST-C score).

What's the new treatment for IgA nephropathy?

UK NICE has approved targeted-release budesonide (Kinpeygo) and sparsentan for IgA nephropathy with persistent proteinuria. Combined with SGLT2 inhibitors and tight BP control, these reduce progression by 50% or more compared to a decade ago.

Can diet reduce protein in urine?

A reduced-salt, Mediterranean-style diet with sensible protein intake can lower urine protein, particularly when combined with prescribed ACE inhibitors, ARBs or SGLT2 inhibitors. Very low-protein diets are not routinely recommended without dietitian supervision.

Nutritional challenges in kidney disease

Many people living with kidney disease have to limit foods because of potassium, phosphate, diabetes, dialysis, appetite changes or simply the time it takes to cook from scratch every day. That can make it harder to keep daily nutrition balanced — particularly for vitamins and minerals that food alone may not fully cover.

Kidney Vitality is a UK-formulated daily nutritional support product designed by Consultant Nephrologist Professor Mohammed Mahdi Althaf with renal nutrition in mind from the start. It keeps doses moderate, leaves out added potassium, phosphate and magnesium, and avoids megadose vitamin A — sitting alongside a kidney-friendly diet, not replacing it.

Why Kidney Vitality fits this need

Built around UK renal guidance

Aligned with KDIGO 2021 Glomerular Diseases, NICE TA908 (sparsentan) and NICE TA916 (budesonide for IgAN).

Designed by a UK Consultant Nephrologist

Formulated and reviewed by Professor Mohammed Mahdi Althaf (GMC 7216325).

Evidence-based by design

Practical UK guidance for adults with IgA nephropathy.

Designed by a UK Consultant Nephrologist

Ready to support your kidney health?

If you have been researching kidney health, supplements, CKD nutrition or kidney-friendly living, Kidney Vitality was developed specifically around those principles by Professor Mohammed Mahdi Althaf (GMC 7216325). Nephrologist Developed Daily Multivitamin.

  • No Added Potassium
  • No Added Magnesium
  • No Added Phosphorus
  • No Added Iron
  • One capsule daily
  • UK GMP — BRCGS, NSF GMP, Halal
Subscribe & Save — £20.39/monthCheck your current multivitamin

✓ Free UK tracked delivery  ·  ✓ Delivered every 30 days  ·  ✓ Pause or cancel anytime  ·  ✓ Never run out

ComparisonKidney VitalityTypical high-street multivitamin
Added potassiumNoneOften included
Added phosphateNoneOften included (E338–E452)
Vitamin A (retinol)No megadoseOften high-dose retinol
Kidney-focused formulationYesNo — general population
Consultant Nephrologist involvementYes (GMC 7216325)No
UK GMP manufacturedYes (BRCGS, NSF GMP)Varies

Food supplement. Not a medicine and not a treatment for kidney disease. Speak with your GP, pharmacist or renal team before starting any new supplement, especially in advanced CKD, on dialysis, post-transplant, pregnant or breastfeeding.

Clinical reviewer

Professor Mohammed Mahdi Althaf

Consultant Nephrologist

Acute Physician

GMC 7216325

View Full Biography

Professor Mohammed Mahdi Althaf is a UK Consultant Nephrologist and Acute Physician with a special interest in chronic kidney disease, AKI prevention and renal nutrition. He combines hospital practice with patient education and clinical guidance review.

View professional profile →
View Credentials
  • MD
  • MSc
  • PgDip (Clin Ed)
  • FRCP
  • FHEA
  • FASN

About this article

Written for UK patients and based on:

  • NICE guidance
  • NHS resources
  • British Dietetic Association guidance
  • Kidney Care UK resources
View methodology

Each article is researched against current UK clinical guidance (NICE NG203, NG118, NG136), NHS patient resources, KDIGO and KDOQI international guidelines, and the British Dietetic Association Renal Nutrition Group. Drafts are written by the Kidney Vitality editorial team and reviewed by a UK Consultant Nephrologist before publication. Content is reviewed on a rolling basis and updated when guidance changes.

Editorial standards

  • Clinically reviewed
  • NHS-aligned
  • NICE-aligned
  • Evidence-based
  • Reviewed before publication
View full editorial process

Every article is researched and written by the Kidney Vitality editorial team using current UK clinical guidance (NICE NG203, NG118, NG136), NHS patient resources, KDIGO/KDOQI international guidelines, and British Dietetic Association renal nutrition guidance. Drafts are reviewed for clinical accuracy by Professor Mohammed Mahdi Althaf, MD, MSc, PgDip (Clin Ed), FRCP, FHEA, FASN (Consultant Nephrologist & Acute Physician, GMC 7216325) before publication. Content is updated when UK guidance changes.

References (4)View Sources
  1. NICE NG203: Chronic kidney disease — assessment and management
  2. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD
  3. KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update
  4. British Dietetic Association — Renal Nutrition Group

Medical disclaimer

This content is educational only and does not replace personalised medical advice.

Read full disclaimer

This page is general information, not personal medical advice. If you have chronic kidney disease, are on dialysis, have had a kidney transplant, are pregnant or breastfeeding, or take prescription medication, please confirm any supplement with your GP, pharmacist or renal team before starting.

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