History:

This patient has had localized vitiligo of many months duration. He has applied 8-methoxypsoralen lotion to the vitiliginous patch on the dorsum of the hand and exposed it 10 minutes to the sun light. Next day he has developed a phototoxic reaction with tense bulla on a background of erythema that extended beyond the border of the vitiliginous patch. This unwanted effect of topical psoralen preparations used in the treatment of vitiligo is commonly encountered in dermatological daily practice even if these preparations are diluted to lower concentrations than what is recommended.