Paediatrics: Henoch–Schonlein purpura

Henoch–Schonlein purpura

Small vessel vasculitis associated with IgA immune complexes. A triad of arthritis, colicky abdominal pain, and palpable, papular, purpuric rash. Characteristically affects prepubertal boys.

Clinical features

•   Skin rash: palpable purpura over buttocks and lower legs. Severe skin vasculitis can lead to oedema (dorsum hand, scrotum, and periorbital).

•   Arthritis: typically short-lived affecting large joints (knees, ankles, or elbows).

•   Gastrointestinal: colicky abdominal pain (commonest), malaena, haematemesis, intussusception, perforation, appendicitis.

•   Renal: dipstick haematuria and proteinuria present (50%). Glomerulonephritis and nephrotic syndrome rare.

Investigations

•   FBC, renal function, dipstick urinalysis, and full renal investigation with biopsy if evidence of renal involvement (crescentic IgA glomerulonephritis).

•   Skin biopsy rarely necessary: leucocytoclastic vasculitis.

•   Abdominal investigations as per symptoms.

Treatment and prognosis

Most cases have a benign course with complete resolution of symptoms within 6wks. NSAIDs help arthritis symptoms. Corticosteroids for abdom-inal pain and arthritis may hasten symptom resolution. Test for haematuria because nephritis and nephritic syndrome carry worse prognosis for hy-pertension and decreased renal function.