A 37-year-old Caucasian man sought care at our clinic for the pruritic patches on his trunk and extremities that had developed 3 days earlier. The patient said that the lesions started on his right arm but had spread to his left arm, posterior legs, and trunk. He reported that the trunk lesions had resolved, but the extremity lesions persisted. He’d had no specific contact exposures.
The patient’s vital signs and cardiopulmonary exam were normal. Examination of the patient’s arms and posterior legs revealed a few faintly erythematous, slightly indurated patches suggestive of urticaria. Examination of the patient’s anterior trunk and back revealed no similar lesions, but he did have a 1.2 cm pigmented patch and 4 mm nodule (FIGURE) on his upper back.
Upon further questioning, the patient indicated that he had noted the pigmented patch for at least 4 years, but was not sure how long the nodular area had been there. He thought it was a birthmark. He grew up spending a lot of time at the beach in the sun and recalled at least one blistering sunburn on his back.
WHAT IS YOUR DIAGNOSIS? HOW WOULD YOU TREAT THIS PATIENT?
