Original article
Treatment of onychomycosis using a submillisecond 1064-nm neodymium:yttrium-aluminum-garnet laser

In vitro results were presented as a poster at the American Academy of Dermatology Annual Meeting, Miami Beach, FL, March 5-10, 2010.
https://doi.org/10.1016/j.jaad.2013.04.054Get rights and content

Background

Laser treatment has emerged as a novel treatment modality for onychomycosis.

Objective

We sought to determine thermal response and optical effects of a submillisecond neodymium:yttrium-aluminum-garnet (Nd:YAG) 1064-nm laser on common fungal nail pathogens, and the clinical efficacy and safety of the Nd:YAG 1064-nm laser on onychomycotic toenails.

Methods

A 4-part in vitro and in vivo study was conducted using a Nd:YAG 1064-nm laser. The first portion evaluated 3 different nail pathogens in suspension at 7 heat and time exposures. The second and third parts of the study irradiated pure fungal colonies. The final portion involved an in vivo treatment of toenails over 5 treatment sessions.

Results

A fungicidal effect for Trichophyton rubrum was seen at 50°C after 15 minutes, and for Epidermophyton floccosum at 50°C after 10 minutes. Limited growth of Scytalidium was seen at 55°C after 5 minutes. No inhibition was observed after laser treatment of fungal colonies or suspensions. In vivo treatment of toenails showed no improvement in Onychomycosis Severity Index score.

Limitations

The Nd:YAG 1064-nm laser was the only laser tested.

Conclusions

Laser treatment of onychomycosis was not related to thermal damage or direct laser effects. In vivo treatment did not result in onychomycosis cure.

Section snippets

In vitro

Three common, but unrelated, nail pathogens were used for the in vitro portion of the study. Trichophyton rubrum, Epidermophyton floccosum, and Scytalidium dimidiatum were grown on agar slants. S hyalinum was selected as a representative nondermatophyte mold. Fungal elements were teased off the colony into sterile water to make a suspension of 0.4 × 104 to 5 × 104 colony-forming unit (CFU)/mL. Each fungal suspension was placed into 8 0.2-mL polymerase chain reaction tubes. The tubes were then

Thermal treatment results

Control plates began to show confluent growth after 4 days of incubation. Reduction in the growth of T rubrum was seen at temperatures of 50°C, held for at least 5 minutes. A fungicidal effect was seen at 50°C with exposure times of 15 minutes. E floccosum showed significantly reduced CFU counts when held at 50°C for 2 minutes and a fungicidal effect was seen at 50°C with exposure times of 10 minutes. S dimidiatum showed confluent growth at every time-temperature treatment except for 55°C for 5

Discussion

Previous in vitro work by Vural et al2 showed statistically significant growth inhibition of T rubrum colonies treated with both the Nd:YAG 1064-nm and 532-nm lasers, supporting laser as a treatment for onychomycosis. The 1064-nm effectiveness was postulated to be a result of photothermolysis caused by absorption of laser light by the melanin found in the cell wall of T rubrum. Photoinactivation of T rubrum was also reported by Bornstein et al3 after irradiation with a combined 870- and 930-nm

References (8)

  • C. Carney et al.

    A new classification system for grading the severity of onychomycosis: onychomycosis severity index

    Arch Dermatol

    (2011)
  • E. Vural et al.

    The effects of laser irradiation on Trichophyton rubrum growth

    Lasers Med Sci

    (2008)
  • E. Bornstein et al.

    Near-infrared photoinactivation of bacteria and fungi at physiologic temperatures

    Photochem Photobiol

    (2009)
  • C. Engelhardt-Zasada et al.

    Influence of temperature on dermatophytes

    Mycopathol Mycol Appl

    (1972)
There are more references available in the full text version of this article.

Cited by (82)

View all citing articles on Scopus

Supported by Cutera Inc, Brisbane, CA.

Disclosure: Dr Elewski has received grants from Cutera Inc and Anacor Pharmaceuticals Inc, and a grant and honoraria from Valeant Pharmaceuticals International Inc. Drs Carney and Cantrell and Ms Warner have no conflicts of interest to declare.

View full text