Image of the Week: Can you identify these cutaneous findings?

An otherwise healthy 50-year-old man presents to his new family physician with a rash that he has had for several years. He mentions that the skin eruption becomes erythematous and pruritic after exercising and when he scratches it. On examination, reddish-brown freckle-like macules are seen on his upper extremities, back, and abdomen. A skin biopsy reveals an increased number of dermal mast cells. Which of the following is most commonly associated with this patient’s likely diagnosis? Learn more about this case, take the quiz, and join the conversation on Figure 1.

The Image of the Week for December 10 is brought to you in partnership with: