Light sensitivity in mycosis fungoides.

Because of suspected photosensitivity, twelve patients suffering from mycosis fungoides have been phototested with various wavebands. Four patients experienced a burning sensation and erythema following sun-exposure, after the disease had progressed to stage II. On phototesting, abnormal reactions were observed in 7 patients. The offending wavebands were situated mostly in the UVA range, but also in the UVB range and in visible light.