The correct answer is all the above (choice “e”).
The differential for round or annular, scaly lesions is lengthy. In addition to all 4 conditions listed above, it includes eczema, basal cell carcinoma, and irritant or contact dermatitis.
With this patient’s history, the diagnosis of fungal infection was not unreasonable. However, the total lack of response to antifungal treatment—along with a negative KOH prep—made that diagnosis questionable at best. Then there was the lack of lymphadenopathy, which would almost certainly have been present with such longstanding infection. Given her country of origin, cutaneous New World leishmaniasis (caused by a protozoan delivered to the patient by an insect vector) was a possibility.
For this patient, skin biopsy with a 4-mm punch was the only way to establish the correct diagnosis. The defect from the biopsy was closed with 5-0 nylon sutures to minimize scarring.
The pathological findings included interface dermatitis, apoptotic keratinocytes, and a brisk periadnexal lymphocytic infiltrate, which—given the morphological and historical context—were entirely consistent with discoid lupus erythematosus (DLE; otherwise known as subacute cutaneous lupus erythematosus). Subsequent bloodwork failed to show any connection with systemic lupus erythematosus (SLE), which is not surprising because only about 18% of DLE cases evolve into SLE.
DLE is more common in women, especially in those with skin of color. The associated lesions are seldom as impressive as this patient’s, manifesting as papulosquamous patches typically found on the ears, neck, face, arms, and other sun-exposed areas. Indeed, it appears that sun exposure is a major trigger for the disease—a clue that can assist with the diagnosis.
In addition to proscribing excessive sun exposure, providers should encourage the use of sunscreen. DLE is often treated with topical steroids. More advanced cases, such as this patient’s, may require oral hydroxychloroquine (200 mg bid). Though these treatments are effective in most cases, DLE can leave serious scarring and/or discoloration, especially in those with darker skin.