Red, edematous, itchy plaques on the extremities
A 77-year-old woman complained of itchy erythematous and edematous plaques of three months’ duration. The eruption involved the extensor aspects of her forearms and the anterior surface of her thighs. Oral antihistamines and a potent topical steroid brought no improvement. Punch biopsy revealed epidermal and dermal edema, scattered neutrophils, and occasional eosinophils. IM triamcinolone initially resulted in improvement, but three weeks later, multiple bullae appeared.