A severe blistering eruption in an elderly patient

Case presentation

A 75-year-old man presents with a severe blistering eruption on his ankle and foot (Figure 1). He recently suffered a small cut on the ankle and began to self-treat it with a herbal cream containing rhus extract. Four days later the eruption developed. It is intensely itchy and is starting to appear on other parts of his body, including the skin on his face and penis.