A 70-year-old man presented with a 4 month history of painful, pruritic rash involving the scalp, face, chest, and back. He had a history of colon cancer and deep venous thrombosis.
A biopsy sample of the rash had been interpreted as eczema, but he had had only minimum improvement with short courses of both topical and systemic corticosteroids and antibiotics.
Examination showed a healthy-looking man with erythematous papules and plaques displaying cornflake-like scale in a seborrheic distribution (figure). Oral and ocular mucosae were normal. Previous serological studies, including antinuclear antibody (ANA), complement, and serum protein electrophoresis, were normal.
What’s the most likely diagnosis ?
