Dermatology

A 17-year-old boy presents with an intermittent asymptomatic rash on his cheeks that he says started 1 year earlier after a trip to Arizona over spring break. He is otherwise healthy, takes no medications, and has no other rashes.

For several weeks, a 25-year-old man has been bothered by a pruritic rash on his hands. He has a history of allergies but is otherwise healthy. He owns 2 dogs.

For 1 month, a 54-year-old woman has had an intensely pruritic eruption on her abdomen, arms, and anterior thighs. She has long-standing hypertension and type 2 diabetes mellitus, which are treated with an angiotensin-converting enzyme inhibitor/diuretic and an oral hypoglycemic agent.

This worsening rash developed after a 40-year-old man was treated with amoxicillin for an upper respiratory tract infection. When the rash started, the amoxicillin was discontinued and azithromycin was prescribed; however, the rash has persisted. The patient has no history of allergies or rashes. He takes no other medications.