Figurate purpuric eruptions on the trunk: acetaminophen-induced rashes.

A 23-year-old man had recurrent erythematous purpuric patches in a transverse-linear arrangement on his back and arms. One week prior to a recent episode, he took acetaminophen for 3 days. Four months earlier, he developed the same purpuric lesions at/around the same anatomical site when he took acetaminophen for pain-relief. A biopsy specimen showed capillaritis and extravasation of erythrocytes in the papillary dermis. A provocation test with acetaminophen confirmed these lesions as drug-induced rashes. The uncommon topographic and morphologic features of the purpuric lesion in this patient might be considered as an unusual expression of pigmented purpuric dermatosis caused by acetaminophen.