A rare cause of rash in elderly: diagnostic dilemma.

To cite: Klair JS, Kaur A, Achanta LM. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014205601 DESCRIPTION Henoch-Schönlein purpura (HSP) is an immunemediated vasculitis associated with IgA deposition within affected organs. It is the most common vasculitis in children; >90% of reported cases occurred in children <10 years old. It is poorly described and under-recognised in adults. Approximately 70% of HSP cases in adults occur in men. HSP is often preceded by an infection, such as a throat infection. The diagnostic criteria for HSP include palpable purpura plus (abdominal pain, biopsy showing predominant IgA deposition, arthritis/arthralgia or renal involvement (haematuria/proteinuria)). The typical rash of HSP is bilateral, symmetric, palpable purpura usually occurring on the legs and buttocks, but it can also be seen on the arms, face and trunk (figure 1A, B). Gastrointestinal symptoms, seen in up to 84% of patients, include nausea, vomiting and colicky abdominal pain. Diagnosis is confirmed with a skin biopsy showing leucocytoclastic vasculitis with positive immunofluorescence of IgA (figure 1C, D), differentiating it from other causes of vasculitis in adults. HSP is managed conservatively with hydration and NSAIDs for arthralgias. However, it does not prevent recurrence of the disease. The palpable purpura tends to relapse repeatedly over many months, but usually remits within 1 year of