Henoch - schonlein (anaphylactoid) purpura

(Edouard Heinrich Henoch, 1820 - 1910, German paediatrist and Johann Lukas Schonlein, 1793 - 1864, German physician), a syndrome of nonthrombocytopenic purpura, arthralgia or arthritis, abdominal pain and renal disease. This disease is of unknown cause but its pathogenesis is related to a generalized angiitis involving arterioles and capillaries. Oedema, haemorrhage and increased permeability of vessels are characteristic findings. The disease affects many tissues, including the synovial membrane.

A classic triad of purpura, abdominal pain and arthritis is diagnostic. Soft tissue oedema may also be evident. The knees, ankles, hips, wrists and small joints of the hand are involved most commonly. The only radiographic abnormality, however, is periarticular soft tissue swelling related to synovial effusion (Fig.1). Patients generally show complete resolution of clinical and radiographic joint abnormalities.

DR/RB