IgA-mediated generalised vasculitis involving small vessels of the skin, GI tract, kidneys, joints, rarely the lungs and CNS
Aetiology
- 75% of cases occur in children age 2-11, rare in infants
- 75% of patients have had a preceding infection (URTI, pharyngeal, GI), most commonly GAS, 1-3 weeks before HSP develops
Clinical presentation
- Purpuric rash typically over buttocks and lower limbs
Investigations
- Clinical diagnosis but other tests may be useful if uncertainty
- Bloods:
- FBC, U+Es, LFTs, inflammatory markers, complement levels
- ANCAs and specific antibodies
- Connective tissue disease screen
- Imaging - CXR and/or CT scan
- Nerve conduction tests
- Tissue biopsy for definative diagnosis in uncertain cases
- Urine dipstick should always be performed to check for renal involvement
Management
- Usually self-limiting within 8 weeks, may be relapses (months-years after resolution)
- Urinalysis and BP should be closely monitored during course of illness due to risk of renal failure - may require nephrology referral