Henoch Schonlein Purpura

Henoch Schonlein Purpura (HSP) - Arthritis and arthralgias occur in 50 to 80% of children with HSP and this may be the presenting feature in 25% of cases. The typical palpable purpuric vasculitic rash on the extensor surfaces is characteristic. 

HSP arthritis is predominantly a large joint arthritis involving knees and ankles, however other joints including wrists and elbows can be affected. The small joints of fingers can also be involved. Affected joints have painful range of movements due to periarticular swelling but the characteristic findings of warmth, erythema and effusion are often absent. Joint disease in HSP is transient and resolves within few days to weeks without any residual deformity. Articular features may reappear for few weeks and then subside. NSAIDs may be used. 

There may also be renal involvement and gut involvement.