Experimental production of DLE lesion with a single exposure to UVB (2.7 MEDs) radiation

Keratotic erythematous lesions developed on the face, ears, neck, and upper back of a 38-year-old man. The patient had a history of photosensitivity to sunlight manifested by the development of new lesions. One week after an MED (2.7 mJ/cm2) was determined using UV-B light, persistent erythema with fine scales were observed at test sites irradiated over 72 mJ/cm2. These lasted for at least 2 months. A biopsy specimen obtained from the test site irradiated at 72 mJ/cm2 showed liquefaction degeneration of the basal cell layer. Within the upper part of the dermis, perivascular and disseminated lymphocytic infiltrates were seen. However, when irradiated again under the same conditions 7 and 12 months after the initial phototest, no persistent erythema was observed.