How would you diagnose these lesions?

A 48-year-old woman presented with a 2-month history of small pruritic blisters on her palms and soles. She denied any history of new exposures, new medications, or anything else that would bring them on. They last approximately 3 weeks, and then begin to dry up before a new crop appears.

How would you diagnose these lesions?

A. Scabies
B. Bullous dermatophyte infection
C. Dyshidrosis
D. Palmoplantar pustulosis
E. Bullous impetigo

Answer on next page

Answer: Palmoplantar pustulosis

A biopsy confirmed the clinical impression of palmoplantar pustulosis. These sterile pustules show histologic features of psoriasis and are very refractory to treatment. Clinical improvement typically is achieved with systemic therapies.

Scabies would be expected to have spread to other parts of the body and to involve the finger webs rather than the palms. Dyshidrosis most often is seen in the finger webs and is not usually seen in well circumscribed patches such as those seen here. Bullous impetigo would be expected to have more crusting and should not keep reappearing in crops.