# Vasculitis

> Vasculitis for NEET-PG: Chapel Hill classification by vessel size, giant cell arteritis, Takayasu, PAN, ANCA-associated and IgA vasculitis pearls.

- Canonical URL: https://prepelephant.com/topics/neet-pg/pathology/vasculitis
- Exam / course: NEET-PG · Subject: Pathology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Vasculitis", PrepElephant, https://prepelephant.com/topics/neet-pg/pathology/vasculitis

## Direct answer

Vasculitis is vessel-wall inflammation with fibrinoid necrosis and downstream ischaemic injury, classified by the Chapel Hill nomenclature according to vessel calibre: large-vessel (giant cell arteritis, Takayasu arteritis), medium-vessel (polyarteritis nodosa, Kawasaki disease) and small-vessel disease, the last split into the ANCA-associated pauci-immune group and the immune-complex group led by IgA vasculitis. For NEET-PG, the age-sex-organ pattern of each syndrome and the c-ANCA versus p-ANCA distinction are the recurring questions.

## What you must remember

- **Giant cell (temporal) arteritis:** granulomatous arteritis of the elderly — temporal headache, jaw claudication, scalp tenderness, markedly raised ESR, polymyalgia rheumatica association; threat of sudden visual loss from anterior ischaemic optic neuropathy — start steroids immediately, since skip lesions may make biopsy negative.
- **Takayasu arteritis:** granulomatous large-vessel disease of young women, commonest in Asia; the aorta and its branches produce the pulseless disease picture — absent pulses, asymmetric blood pressure, limb claudication, renovascular hypertension.
- **Polyarteritis nodosa:** segmental transmural necrotising arteritis at branch points, linked to hepatitis B; renal, mesenteric, cutaneous and nerve involvement producing mononeuritis multiplex — but it spares glomeruli and pulmonary arteries, and is ANCA-negative.
- **Kawasaki disease:** medium-vessel vasculitis of young children — fever with conjunctivitis, oral changes, rash, extremity changes and cervical nodes; coronary artery aneurysms are the feared complication, treated with intravenous immunoglobulin and aspirin.
- **ANCA-associated vasculitides:** pauci-immune necrotising small-vessel disease — granulomatosis with polyangiitis (c-ANCA/PR3; respiratory tract disease with necrotising glomerulonephritis), microscopic polyangiitis (p-ANCA/MPO; glomerulonephritis with pulmonary capillaritis, no granulomas, no asthma) and eosinophilic granulomatosis with polyangiitis (asthma, marked eosinophilia, p-ANCA often positive).
- **IgA (Henoch-Schonlein) vasculitis:** childhood immune-complex disease after respiratory infection — palpable purpura on buttocks and legs, arthralgia, abdominal pain with intussusception risk, and nephritis identical to IgA nephropathy.
- **Other associations:** cryoglobulinaemic vasculitis with hepatitis C, Behcet disease with oral-genital ulcers and uveitis, and drug-induced ANCA vasculitis (hydralazine).

## Common confusion

The trap is two similar names: polyarteritis nodosa versus microscopic polyangiitis. PAN is a medium-vessel, hepatitis B-linked, ANCA-negative disease that spares glomeruli and lungs, whereas microscopic polyangiitis is a small-vessel, p-ANCA-positive, pauci-immune disease that typically causes glomerulonephritis and pulmonary capillaritis. Within the ANCA group, granulomatosis with polyangiitis involves the respiratory tract with granulomas, microscopic polyangiitis does neither, and EGPA stands apart with asthma and eosinophilia. Finally, c-ANCA (PR3) and p-ANCA (MPO) are named by their immunofluorescence pattern, with specificity residing in the ELISA.

## Exam-focused takeaway

NEET-PG stems on vasculitis are pattern-recognition vignettes: an elderly person with headache and high ESR needing immediate steroids (giant cell arteritis), a young woman with absent pulses (Takayasu), a hepatitis B patient with mononeuritis multiplex (PAN), a child with fever and desquamation needing immunoglobulin (Kawasaki), or a child with palpable purpura and abdominal pain (IgA vasculitis). Matching questions test the ANCA pattern, granulomas and vessel calibre of each entity, with one-liners on fibrinoid necrosis, linked infections and drugs. Learn each syndrome as age, vessel, antigen and organ.

## Frequently asked questions

### What differentiates giant cell arteritis from Takayasu arteritis?

Both are granulomatous large-vessel arteritides, but giant cell arteritis affects those over 50 with headache and visual risk, while Takayasu affects young women, producing pulseless disease of aorta and branches.

### Why must steroids precede biopsy in suspected temporal arteritis?

Because skip lesions may be missed and blindness can occur at any time; corticosteroids are started immediately and biopsy remains valid for weeks.

### How do PAN and microscopic polyangiitis differ?

PAN is a medium-vessel, hepatitis B-associated, ANCA-negative disease sparing glomeruli and lungs; microscopic polyangiitis is a small-vessel, p-ANCA-positive, pauci-immune disease causing glomerulonephritis and alveolar haemorrhage.

### What is IgA vasculitis?

A childhood immune-complex small-vessel vasculitis with palpable purpura, arthralgia, abdominal pain and nephritis, often following an upper respiratory infection.

### Which ANCA pattern goes with which disease?

c-ANCA against proteinase 3 suggests granulomatosis with polyangiitis; p-ANCA against myeloperoxidase suggests microscopic polyangiitis and, often, eosinophilic granulomatosis with polyangiitis.