Grouped Pustules on an Erythematous Base - On physical examination, grouped, coalescing pustules that had scalloped borders on an erythematous base and that were tender to palpation were seen on the left arm (Panel A). One of the pustules was unroofed (i.e., the top of the pustule was removed) and the base scraped, smeared onto a glass slide, and stained with Wright–Giemsa stain (Tzanck smear). Microscopic examination revealed numerous multinucleated giant cells with molded nuclei and marginated chromatin (Panel B), which together suggested a human herpesvirus infection. #Clinical #Derm #Pathology #Herpes #Arm #Pustules #Tzsanck #Smear #Microscopy #NEJM