Parakeratosis, acanthosis, and scattered dyskeratotic cells were seen in the epidermis. A dermal lichenoid lymphocytic infiltrate with occasional eosinophils and pigment incontinence were also present.
Treatment consisted of the use of topical 0.05% fluocinonide cream and a broad-spectrum sunscreen, sun avoidance, and discontinuation of sulfamethoxazole-trimethoprim therapy. The lesions slowly resolved over several weeks. Postinflammatory hyperpigmentation was noted at involved sites during the resolution phase.