14-year-old boy with painful nail changes.

Doxycycline is a classically implicated cause of phototoxic reactions. Photo-onycholysis is a rare manifestation of phototoxicity. Nail changes may typically include nail pain, subungual hemorrhages, or distal onycholysis. Self-resolution can be expected in 3 to 6 months. Patients prescribed doxycycline should be counseled about the potential for phototoxicity and the need for appropriate sun protection while taking the medication.