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Systemic treatment of onychomycosis can produce side effects that are undesirable. Lasers used as an adjunct to topical agents may be another effective approach to treating onychomycosis.
The place of lasers is likely to be an adjunct in the treatment of onychomycosis, according to Jason Rivers, M.D., a dermatologist at Pacific Dermesthetics in Vancouver, British Columbia, and Clinical Professor of Dermatology at the University of British Columbia.
"Onychomycosis is a significant problem, and we know medical therapy is often ineffective," says Dr. Rivers. "Even though there can be mycologic cures, patients can still have disease in the nails. We also understand that adverse reactions from oral medications are not inconsequential in some individuals."
If lasers can offer a clinical cure or a significant improvement, they can be of value for patients, says Dr. Rivers. "People want to be able to go to the beach again," he says.
Patients with diabetes and patients with psoriasis are more likely to develop onychomycosis, and the source of onychomycosis is organisms like dermatophytes, yeast and moulds.
If lasers are used to manage onychomycosis, the wavelength should be such that it sufficiently penetrates the nail, explains Dr. Rivers.
While lasers have not yet been approved for mycologic cures, lasers have demonstrated some ability to improve the cosmetic appearance of nails. "So far, the devices have been approved for temporary clearance of nails by the Food and Drug Administration," says Dr. Rivers.
Looking at the evidence for lasers, Dr. Rivers pointed to an in vitro pilot study that concluded Nd:YAG laser treatment of Trichophyton rubrum colonies was not successful in inhibiting fungal growth.1
A study from Japan looked at 37 affected toenails treated with a 1,064 nm Nd:YAG laser. A total of 30 of the 37 toenails had moderate to complete clearance about four months after the final treatment. A total of 19 toenails were completely clear and tested negative for fungal infection.2 While the data of the study were positive, Dr. Rivers notes a limitation of the research is a short follow-up period.
Still another exploration of the use of laser to manage onychomycosis saw the use of an Nd:YAG laser in both in vitro and in vivo experiments. Investigators saw a fungicidal effect for Trichophyton rubrum at 50 degrees Celsius after 15 minutes of exposure, and such an effect for Epidermophyton floccosum at 50 degrees Celsius after 10 minutes. Investigators observed limited growth of Scytalidium at 55 degrees Celsius after five minutes.
However, they witnessed an absence of inhibition after laser treatment of fungal colonies or suspensions. In vivo, the therapy of toenails resulted in no enhancement in the Onychomycosis Severity Index score.3
Dr. Rivers talked with Dermatology Times about his own experience in using lasers to treat onychomycosis, noting that cultures were performed to confirm the presence of onychomycosis. Patients underwent two or more treatments with a laser that took place at least one month apart. The results were validated by a third party, using a computer software program that can validate the amount of nail involvement post-treatment.
Dr. Rivers notes that, when oral treatments for onychomycosis are administered, it takes many months for the nail plate to grow out. His experience with lasers suggests that nail plates grow out more rapidly with the use of lasers. "There seems to be some acceleration of growth [of the nail] that we see," he says.
Ultimately, lasers may prove to be a good adjunct to other therapies like topical antifungal agents. Dr. Rivers pointed to a recent study of 24 patients that found the use of a fractional carbon-dioxide laser, administered in three sessions at four-week intervals, plus a topical antifungal cream produced a 92% clinical response and a 50% complete response with a negative microscopic result. There was no recurrence three months after the last treatment session.4
Several issues need to be clarified, such as the optimal wavelength, treatment parameters, and rate of long term clearance. The future may see the expanded use of lasers to treat other nail conditions like psoriasis, adds Dr. Rivers.
Dr. Rivers has no relevant disclosures.
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Journal of Drugs in Dermatology. 2012 Apr;11(4):496-504.
Journal of the American Academy ofDermatology. 2013 Oct;69(4):578-82.
Journal of the American Academy of Dermatology. 2014 May;70(5):91-23.