Induction of Darier-White disease with UVB radiation in a clinically photo-insensitive patient.

Combination UVA/UVB radiation and UVB radiation alone have been shown to induce the lesions of Darier-White disease. However, 6% of patients with Darier-White disease claim that sunlight ameliorates their condition. We performed an unblinded, side-by-side controlled trial of UVB, UVA, and combination UVB/UVA phototherapy in a patient with historically photoameliorated Darier-White disease to determine whether phototherapy was beneficial, to determine whether phototherapy-related heat was detrimental, and to confirm, with appropriate controls, the action spectrum of the disease. Phototherapy with radiation in the UVB but not UVA spectrum evoked Darier-White disease in this patient, both clinically and histologically. UVB radiation was capable of inducing Darier-White disease in vivo in spite of a history of photoamelioration, whereas UVA radiation alone and the heat associated with phototherapy in our protocol had no effect on the disease.