Severe polymorphic erythema due to interferon α-2b during treatment of hairy cell leukemia

A 54-year-old woman with hairy cell leukemia developed severe polymorphic erythema and blisters on the trunk and limbs after injection of interferon (IFN) α-2b. Skin biopsy revealed lymphocytic exocytosis and perivascular lymphocytic infiltrate in the dermis, and the lesions improved after methylprednisolone pulse therapy. Although injection-site reactions have been observed after injection of IFNα-2b, this is the first report of a widespread cutaneous reaction to IFNα-2b