Laser treatment of onychomycosis: an in vitro pilot study

Background: Laser treatment of onychomycosis is the object of considerable interest. Laser therapy could be a safe and cost-effective treatment modality without the disadvantages of drugs. Some studies have described the inhibitory effects of lasers on the growth of fungal colonies. We therefore examined the effects of various laser wavelengths, which have previously shown inhibitory potential, on the fungal isolate Trichophyton rubrum. Patients and Methods: Isolates of fungal colonies were placed clockwise on culture plates. Each culture plate was irradiated on one half with one of the following treatment regimens: 1064 nm-Q-switched Nd:YAG laser at 4 J/cm(2) and 8 J/cm(2); 532 nm-Q-switched Nd: YAG laser at 8 J/cm(2); 1064 nm-long-pulsed Nd:YAG laser at 45 J/cm(2) or 100 J/cm(2). The other half remained untreated. Standardized photographs were taken and areas of treated and untreated colonies were compared for growth inhibition. Results: There was no inhibition of fungal growth in any of the treated plates. Differences in size between treated and untreated colonies were not significant (p > 0.10). Conclusions: In this in vitro study Nd:YAG laser treatment of Trichophyton rubrum colonies failed to inhibit fungal growth. Nevertheless there might be an effectiveness in vivo which has to be clarified by clinical studies.