What caused these highly pruritic blisters?

Case:
An 80-year-old man presents for evaluation of highly pruritic blisters on the sides of his hands.

Which of the following would you include in the differential?

A. Contact dermatitis.
B. Dyshidrosis.
C. Bullous pemphigoid.
D. Scabies.
E. Pustular psoriasis.

(Continued on next page.)

Case, continued

Further examination revealed 2+ pitting edema of both lower extremities. Skin biopsy results were interpreted as consistent with a dyshidrosis or id reaction to stasis dermatitis. A diuretic and a topical corticosteroid cream were prescribed. The patient returned 1 month later; lower extremity edema had resolved, but the lesions on his hands had worsened.

What action would you take?

F. Order patch testing.
G. Order blood test for porphyrins.
H. Discontinue all unnecessary medications.
I. Start an oral antiviral agent, such as valacyclovir.
J. Repeat the skin biopsy.

(Answer on next page.)

Answer: Bullous pemphigoid

A second skin biopsy, J, including immunofluorescence was performed; the results showed changes consistent with bullous pemphigoid, C. Dapsone with cimetidine was prescribed as a steroid-sparing regimen in addition to a more potent topical corticosteroid. The blisters resolved. When the patient was seen in followup over the next 6 months, his condition stayed in remission.