The treatment of vitiligo with topical application of psoralen ointment has not always proved to be effective, in part because of the actinodermatitis resulting from exposure of the vitiliginous areas to ultraviolet light.1 Such untoward reactions have somewhat discouraged use of these drugs in local treatment of this disease. Results achieved with topical ointment of hydrocortisone in certain dermatoses have demonstrated its anti-inflammatory action against pruritus, edema, erythema, and scaling.*It was hoped, therefore, that this local inhibiting inflammatory reaction of hydrocortisone might be utilized to prevent solar dermatitis and to permit use of higher concentrations of psoralens locally. This study was undertaken to determine whether hydrocortisone can prevent or reduce the intensity of the actinodermatitis caused by ultraviolet light in treatment of vitiligo with psoralens. Previous observations of this inflammation-inhibiting reaction of hydrocortisone have been made with the use of local injections of