# IgA Vasculitis (Henoch-Schonlein Purpura)

> IgA vasculitis for NEET-PG Dermatology, covering the classic tetrad, platelet-normal purpura, the intussusception warning, renal follow-up and treatment.

- Canonical URL: https://prepelephant.com/topics/neet-pg/dermatology/iga-vasculitis-henoch-schonlein-purpura
- Exam / course: NEET-PG · Subject: Dermatology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Rook's Textbook of Dermatology; Nelson Textbook of Pediatrics
- How to cite: "IgA Vasculitis (Henoch-Schonlein Purpura)", PrepElephant, https://prepelephant.com/topics/neet-pg/dermatology/iga-vasculitis-henoch-schonlein-purpura

## Direct answer

IgA vasculitis, formerly Henoch-Schonlein purpura, is an IgA-dominant immune complex vasculitis of small vessels that mainly affects children. Its classic tetrad is palpable purpura on the legs and buttocks, arthritis, abdominal pain and nephritis, with IgA deposits on biopsy. The platelet count is normal, which separates it from immune thrombocytopenic purpura, and renal involvement decides the long-term outcome.

## What you must remember

- **Classic tetrad:** palpable purpura on the lower limbs and buttocks, arthritis or arthralgia of the knees and ankles, colicky abdominal pain and nephritis.
- **Age:** predominantly a childhood disease, most often in early childhood; adults tend to have more persistent renal disease.
- **Platelets:** a normal count is the key laboratory point against immune thrombocytopenic purpura.
- **Histology:** leukocytoclastic vasculitis with IgA deposits in vessel walls, the defining finding on direct immunofluorescence.
- **Gut complications:** intussusception and gastrointestinal bleeding are the serious abdominal complications, and ultrasound is the usual first test.
- **Renal follow-up:** urine dipstick and blood pressure checks continue for several months, because persistent proteinuria or a reduced filtration rate sets the prognosis.
- **Most cases:** the disease is usually self-limiting over weeks, with supportive care and analgesia, and corticosteroids reserved for severe gut or joint features.

## A pattern-based approach to the child with purpura

A 6-year-old boy presents with palpable purpura on both legs, knee pain and colicky abdominal pain after a sore throat. His platelet count is normal, and urine shows blood and protein.

1. **Confirm the purpura is palpable:** raised lesions on the legs and buttocks, with normal platelets, point to vasculitis rather than a bleeding disorder.
2. **Map the organs:** ask about joint pain, colicky abdominal pain, melaena and urinary change, because each one signals a separate system at risk.
3. **Check the urine:** dipstick and microscopy for haematuria and proteinuria, together with serum creatinine and blood pressure, set the renal baseline.
4. **Image the abdomen when pain is severe:** ultrasound excludes intussusception, which can occur in this condition and needs urgent surgical review.
5. **Look for a trigger:** a recent upper respiratory infection or a streptococcal history is a common antecedent, and drugs should be checked too.
6. **Treat and monitor:** supportive care, analgesia and fluids come first, corticosteroids are reserved for severe abdominal or joint disease, and urine testing continues for months.

## Where the exam tries to catch you

Three traps recur in paediatric questions on this condition.

- **Trap:** diagnosing immune thrombocytopenic purpura from purpura on the legs. **Correct:** IgA vasculitis has a normal platelet count, and purpura with arthritis and abdominal pain points to vasculitis.
- **Trap:** dismissing colicky abdominal pain as gastroenteritis. **Correct:** intussusception is a recognised complication, so ultrasound is needed when the pain is severe or recurrent.
- **Trap:** stopping urine monitoring once the rash fades. **Correct:** nephritis can appear weeks after the rash, so renal follow-up continues for months.

## Frequently asked questions

### Which findings make up the classic tetrad of IgA vasculitis?

The classic tetrad is palpable purpura, arthritis or arthralgia, abdominal pain and nephritis. Palpable purpura on the lower limbs and buttocks is usually the first sign, and IgA vasculitis is confirmed by IgA deposits on biopsy.

### Why must abdominal pain in IgA vasculitis be investigated?

Abdominal pain in IgA vasculitis can signal intussusception or gastrointestinal bleeding, and both need prompt assessment. Ultrasound is the usual first test in a child with IgA vasculitis who has severe or recurrent pain.

### Does IgA vasculitis always need corticosteroids?

Most children with IgA vasculitis recover with supportive care, analgesia and observation, because the disease is usually self-limiting. Corticosteroids are reserved for severe abdominal pain, marked joint involvement or intussusception-related problems, since evidence that they prevent nephritis is limited.

### How long should a child with IgA vasculitis be monitored for kidney involvement?

Urine testing for protein and blood, with blood pressure checks, continues for several months after the rash appears. Nephritis can develop late, and persistent proteinuria or a reduced filtration rate sets the long-term prognosis of IgA vasculitis.