A previously healthy 42-year-old man presented with a 2-day history of an intensely pruritic erythematous well-demarcated plaque on his right anterior ankle (Fig. 1a) and ipsilateral foot dorsum (Fig. 1b). Multiple hemorrhagic blisters and vesicles were noted on the surface of the plaque. There were no other cutaneous nor mucosal lesions on physical examination. The patient consistently denied prior use of any medications. He referred having developed the plaque about 12h after returning from a fishing trip.