A purpuric rash.

Kelly is 28 years of age and a recreational sea swimmer and surfer. He presented with a rash on both arms of 6 months duration. Kelly said a similar eruption occurred 12 months previously and resolved in a few weeks with 1% hydrocortisone cream. He has no significant past history, is not on any medication, and there is no recent history of trauma or contact with insects or animals. Physical examination revealed multiple, flat, nonblanching dark red lesions on the medial aspect of both arms (Figure 1, 2). The rest of the physical examination was unremarkable. Full blood examination revealed normal levels of haemoglobin, white cells and platelets, and coagulation studies are normal.