Laser treatment of onychomycosis due to Neoscytalidium dimidiatum: An open prospective study.

Conventional systemic and topical treatments have proven ineffective for the treatment of onychomycosis caused by Neoscytalidium dimidiatum. Our aim was to evaluate the effectiveness and safety of laser monotherapy for the treatment of onychomycosis caused by this pathogen. Patients with clinical onychomycosis of the toenails and positive results both on direct mycological examination and N. dimidiatum culture underwent four 1064 nm Nd:YAG laser sessions with 6-week intervals between sessions. Participants were monitored by clinical examination supported by dermoscopy, measurement of diseased nail and the onychomycosis severity index (OSI), and by mycological examination for 12 months after completion of treatment. Treatment outcome was based on clinical and laboratory criteria and was divided in complete or partial cure, clinical improvement, treatment failure and relapse. No patient had complete or partial cure at any time during the study. Clinical improvement was observed in 40.6% of the patients at the end of the laser sessions; however, it did not persist during the follow-up. Treatment failure was observed in 64.7% of the patients at the end of 12 month follow-up period. Direct microscopy and culture results remained positive in most patients. Adverse events, in addition to treatment-related pain, were observed and considered severe in one case. The 1064 nm Nd:YAG laser was not able to cure onychomycosis caused by N. dimidiatum but temporarily improved the clinical appearance of the nail; however, adverse events may occur.