A 36-year old man has a 4-week history of a generalized, intensely pruritic papular rash. He is otherwise well. His
9-year-old son also has itching. On examination, there is a generalized rash consisting of excoriated papules and vesicles on wrists, sides of fingers, arms, and buttocks. No other abnormalities are noted. Which one of the following is the most likely diagnosis? ...