REPORT OF A CASE
A 63-year-old man with a history of polycythemia vera treated with phlebotomy presented with a 2-day history of a pustular skin eruption. The patient was seen 5 days earlier for an upper respiratory infection; ampicillin (500 mg orally twice daily), pseudoephedrine hydrochloride (Sudafed), and cough medicine (Robitussin DM) were prescribed. The patient had been seen in our clinic earlier in the year for a mild pustular eruption on the vertex of his scalp diagnosed as superficial folliculitis, which cleared with topical antibiotics and Hibiclens soap (chlorhexidine gluconate).Physical examination disclosed numerous pustules on the scalp, face, and neck extending to the trunk (Figure 1 and Figure 2). Gram's stain showed neutrophils but no organisms. Bacterial cultures from representative pustules were all negative, except one positive for Propionibacterium acnes. Tzanck smear and viral cultures were negative as were fungal and acid-fast bacilli cultures. A biopsy specimen is