Abstract
Clinically, photosensitivity is clearly part of both lupus erythematosus and dermatomyositis, but the prevalence of this reaction varies. Photosensitivity does not appear to be part of the disease spectrum of scleroderma or part of the clinical picture of vasculitis. Implications of photosensitivity in both lupus erythematosus and dermatomyositis are systemic. The pathogenesis of photosensitivity in lupus erythematosus and dermatomyositis is not fully understood. The presence of photosensitivity has therapeutic implications.