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.

Lichenoid photoeruption is a rare dermatosis associated with advanced HIV disease. The clinical differential diagnosis includes idiopathic lichen planus, lichen planus actinicus, Kaposi sarcoma, and sarcoidosis.

In a retrospective review of 32 patients with a histologic diagnosis of lichen planus, lichenoid dermatitis, or photodermatitis seen over a 15-month period in the dermatology clinics of the University of California at San Francisco, Berger and Dhar¹ identified a subset of 12 HIV-infected patients with initially photodistributed eruptions. Ten of the 12 patients were African American, and 10 were receiving potentially photosensitizing medications at the onset of their eruptions. All 12 patients had acquired immunodeficiency syndrome with CD4⁺ cell counts of less than 50/µL, and 8 of the 12 had a uniform clinical pattern with pruritic violaceous plaques that began on sun-exposed skin. In 7 of the 8 patients, the plaques later involved non–sun-exposed areas. No mucosal lesions were present except for occasional involvement of the lower lip. Histologically, features of lichenoid drug eruptions or hypertrophic lichen planus were primarily seen. The authors concluded that idiopathic lichen planus seemed to be less common than lichenoid photoeruptions in their population of HIV-infected patients.