Several months ago, lesions appeared on both of this 48-year-old woman’s hands. They have been completely unresponsive to any of the treatments prescribed by her primary care provider, including oral (terbinafine) and topical antifungal medications.
The lesions, which are asymptomatic, manifested slowly. They first appeared on the dorsa of her hands and then gradually spread until they covered the central portion of both hands. The lesions wax and wane in terms of thickness and extent but never disappear.
The patient denies similar lesions elsewhere. She also denies contact with animals or children. She has never been immunosuppressed and is quite healthy aside from her skin problems. She has a family history but no personal history of diabetes.
EXAMINATION
The condition affects both hands equally. It is composed of intradermal reddish brown papules and plaques that cover the metacarpal areas and extend onto the proximal interphalangeal skin and the distal dorsa. No epidermal component (scale or other broken skin surface) is seen.
The margins of the lesions are arciform, slightly raised, and smooth. The centers of several are concave.
What is the diagnosis?