Photobiology of lupus erythematosus.

Ultraviolet radiation in the 2850 to 3150 angstrom range can produce abnormal cutaneous reactions and exacerbation of systemic manifestations in some cases of subacute and acute systemic lupus erythematosus. It may also be responsible for cutaneous lesions and systemic involvement in rare cases of chronic discoid lupus erythematosus--probably those with disseminated lesions. The pathophysiological mechanism producing these photobiological effects in lupus erythematosus remains unknown.