A 29-year-old man presented to the emergency department (ED) with a rash across his chest and abdomen. The rash began 2 hours before his arrival and was initially pruritic, but subsequently became painful. The patient also complained of acute onset of aching pain in both hips and his left arm. He denied associated chest pain or dyspnea, and had no paresthesias or disequilibrium. Routine laboratory studies and chest radiograph were normal. Earlier in the day, the patient had completed a dive to 235 feet in depth in Lake Mead, Nevada, but reported a very controlled ascent with appropriate decompression stops. Two days earlier, he had completed a dive to 315 feet in Lake Mead without any problems.