Abstract: Photo-onycholysis is a rare form of nail separation, usually triggered by enhanced ultraviolet radiation. This article reports three cases of children with refractory periungual warts who developed distal lunula-like nail separation after two times of 5-aminolevulinic acid photodynamic therapy (ALA-PDT). Three children were diagnosed as photo-onycholysis, and were treated with oral multivitamin tablets for 2-3 months, then the nail beds returned to normal. This article not only reveals the potential adverse reactions of ALA-PDT in the treatment of periungual warts in children but also provides a reference for the treatment of photo-onycholysis.

Key words: 5-aminolevulinic acid, photodynamic therapy, photo-onycholysis, periungual warts