1,064-nm and 532-nm picosecond neodymium-doped:yttrium-aluminum-garnet laser treatment for longitudinal melanonychia: a case report

Melanonychia is a common pigmentary disorder characterized by black or brownish longitudinal pigmentation of the nail plate.It is usually benign but can cause aesthetic concerns.Herein, we describe the case of a 29-year-old female diagnosed with benign longitudinal melanonychia, and treated with two different wavelengths of picosecond neodymium-doped:yttrium-aluminum-garnet (ps Nd:YAG) laser.The lesion was divided into two halves.The proximal half was treated with a 1,064-nm ps Nd:YAG laser and the distal half was treated with a 532-nm ps Nd:YAG laser.After a single treatment session, both sides exhibited immediate and marked improvement.However, after three weeks pigmentation that had grown out from the nail matrix was evident on the proximal nail plate.This case suggests that ps Nd:YAG lasers may be effective for immediate resolution of pigmentation on the nail plate, but fundamental treatment of the nail matrix is necessary to prevent recurrence.