The 2 punch biopsy specimens showed a normal epidermis, with papillary dermal edema. There was an intense perivenular and interstitial infiltrate of neutrophils admixed with extravasated erythrocytes. Fibrin deposition was present in and around several vessel walls.
Results of a serum chemistry profile and urinalysis were normal, as were the hematocrit, prothrombin time, and applied partial thromboplastin time. The hemoglobin, platelet, and complement levels were also normal. A chest radiograph revealed no abnormalities. Serologic tests were negative for antinuclear antibody, rheumatoid factor, and hepatitis A, B, and C. The white blood cell count was elevated to 26×109/L, with a mild left shift, and the erythrocyte sedimentation rate was 30 mm/h (reference range, 0-15 mm/h). The patient did not respond to treatment with hydroxyzine hydrochloride and doxepin hydrochloride, so he was treated with prednisone (60 mg/d), the dosage of which was tapered by 10 mg every 5 days. On follow-up 17 days later, the patient was found to be free of any skin involvement, and the prednisone therapy was discontinued.
Pruritic, Painful Eruption. Arch Dermatol. 1998;134(2):231-236. doi: