A tender multilocular blister has developed on a man’s finger over a few days. What is the cause and how may it be treated?
A 37-year-old man developed a tender multilocular blister on the distal aspect of his right ring finger (Figure 1). The blister had appeared over the previous three days. A Tzanck smear (a scraping of the blister contents fixed on a glass slide and stained) revealed enlarged keratinocytes that were multinucleated (Figure 2).