Recurrent annular plaques in a healthy young woman

A 35-year-old woman presented with recurrent intensely pruritic erythematous plaques over both forearms for 8 months, with no systemic symptoms or identifiable triggers. Clinical examination showed well-defined oedematous papules and plaques with a tendency for centrifugal spread and central resolution. Histopathology revealed epidermal ulceration with parakeratosis, massive dermal oedema and a dense neutrophilic infiltrate with leucocytoclasia and histiocytes in the upper and mid dermis, with no evidence of vasculitis.