What explains this man’s bullae?

After having been outdoors in July, a 35-year-old man presented with a sudden onset of itchy blisters confined to both feet and lower legs. He was otherwise healthy and did not remember feeling that he had been bitten.

What explains this man’s bullae?

A. Bullous insect bite reaction
B. Bullous tinea pedis
C. Bullous pemphigoid
D. Dyshidrosis
E. Bullous impetigo

Answer on next page

Answer: Insect bite

This man’s lesions were a bullous reaction to an insect bite, mostly likely that of chiggers. He responded quickly to a high-potency topical corticosteroid cream.

In bullous tinea pedis, toe-web and plantar involvement is typical. Bullous pemphigoid usually occurs in older patients and has a more erythematous base. Dyshidrosis typically occurs on the plantar surface and the edges of the toes. Because impetigo blisters are so fragile, bullous impetigo likely would have lots of crusting, unlike what is seen in here.