Toe Nail Fungus Laser Treatment: Does It Really Work?

Tough to get rid of, treatments for toenail fungus have become a widespread search. Several therapies—topical, oral, and surgical—have been used to treat nail fungus but have also come, unfortunately, with several difficulties.¹ For instance, topical medication for onychomycosis is not very effective due to the dense structure of the nail, making the medication hard to penetrate to deeper layers. Oral antifungal medications have a good effect for some, but the side effects, such as liver toxicity or sensitivity to sunlight, are not tolerable. Surgical treatments affect the appearance of the nail and the infection may easily come back.² Thus, nail laser treatments have become a growing trend for the treatment of toenail fungus infections, can be used for all ages in patients with or without kidney disease, and have very few side effects. But just how effective are they?

Nail Fungus Basics

Onychomycosis, generally termed “nail fungus,” is an infection of the base of the nail and the nail bed. It is typically caused by fungal or yeast overgrowth. It is created by fungal or yeast spores that enter the nail and eat the keratin, the main component of nails, within the nail. This messes up the nail matrix (where the nail is made at the back edge of the nail) and causes the nail to become thicker and have discoloration.²

Laser Basics

Lasers are beams of light created by one wavelength, where the wavelength is specific to what the treatment is targeting. The targets within the body consist of light absorbing molecules or cells, called chromophores, which then absorb the wavelength. The two major toenail fungus lasers used for treatment are the Nd:YAG laser and the Carbon Dioxide laser.²

Laser Treatment

How it works

The laser acts in a grid like motion on the nail in pulses targeting the fungus. It works by heating the chromophores within the fungus. One study observed that to completely kill the fungus, the temperature needs to be between 43–51 °C.^2,3 However, another study found that temperatures needed to exceed 50 °C to completely clear the fungus. Furthermore, if temperatures were not high enough, the laser could stimulate the growth of Microsporum gypseum and Trichophyton rubrum.^2,4

Heating the dermal tissue to temperatures above 40 °C results in pain in humans. Thus, the lasers are emitted in pulses so you only feel a little bit of heat from the laser.⁵ If the laser treatments are successful and the fungus is successfully destroyed, the appearance of the nail does not change. You still have to wait for the nail to grow out to become clear. Once you then trim out the discolored nail as it grows, the toenail will become clear again.⁵

Nd:YAG toenail laser treatment

The most commonly used laser for toenail fungus laser treatment is the Nd:YAG laser because it can effectively reach the depth of the nail bed and the base of the nail: the sites of the fungus colony.⁵ During treatments using the Nd:YAG laser, the laser acts on the chromophore of the fungal tissue. Chromophores are light-absorbing molecules or cells that heat up when absorbing laser light.² When these chromophores of the fungus absorb enough light and heat up to high enough temperature, the fungus becomes damaged and is destroyed.²

Various studies have examined the efficacy of the long pulsed 1064 nm Nd:YAG laser for treatment of onychomycosis. The Nd:YAG laser is most effective on nails infected with T. rubrum, which is the most common pathogen associated with onychomycosis.² Studies have identified Xanthomegnin as the chromophore of T. rubrum.^2,6 The Nd:YAG laser is also effective at treating nails infected with T. mentagrophytes and C. albicans.^7,8 Exact parameters to use for treatment have not been established yet. Different studies have used varying parameters and treatment plans, which may partly explain the varying results on efficacy of the laser.

In summary, Wanitphakdeepdecha et al. and Moon et al. both concluded that 1064 nm long-pulsed Nd:YAG laser is an effective treatment for onychomycosis (Table 1).^7,9 However, a study conducted by Kim et al. concluded that for cases of severe onychomycoses, use of the 1064 nm long-pulsed Nd:YAG laser alone was not enough for treatment. Findings from this study suggest combination therapy if considering laser treatment for severe cases of onychomycoses (Table 1).¹⁰

Diode toenail laser treatment

Renner et al. conducted a clinical trial that assessed the efficacy of a 1064 nm diode laser therapy for treatment of onychomycosis. A total of 24 patients were included. All patients were treated with the diode laser at least twice at 8-week intervals. Nails were then evaluated 3.2 months following the initiation of treatment. The researchers utilized the Onychomycosis Severity Index (OSI), a numeric classification system used for grading the severity of onychomycosis, to evaluate efficacy of the laser treatment.¹¹

Patients who had a positive fungal culture and had not received any prior antimycotic treatment had a mean improvement of 25% in their OSI scores following treatment. However, patients with severe onychomycosis, which was determined by a high OSI score, only improved by 14%. Recurrence rates were not assessed. The authors concluded that the diode laser therapy can be effective at treating onychomycosis, and some groups, such as those with lower OSI scores, may benefit from treatment more than others.¹¹ 

Carbon dioxide toenail laser treatment

The carbon dioxide laser has been applied for toenail fungus with high cure rate and low recurrence rate.¹² A scientific study assessed the efficacy of a fractional CO2 laser combined with topical antifungal cream for 3 months with three toenail laser treatment sessions spaced 4 weeks apart.¹³ At 3 months and 6 months following treatment, the researchers observed a 92% and 80% cure rate, respectively.

As opposed to the photothermalysis effect of the Nd:YAG laser, the carbon dioxide uses a photothermal effect: the fungal tissue is heated; the water within the fungal tissue is converted into steam, which causes swelling and increased pressure within the fungal body, leading to micro-explosions and, eventually, fungal death.² It is also possible that the CO2 laser creates microscopic holes on the nail bed, which may increase the absorption of the topical antifungal agent.^2,13

Summary

Though the use of lasers has increased in popularity, there is no cure-all for nail fungal infections. Rather, there are certain treatments that are best for each stage of the infection.¹⁴ Device therapies have several advantages, but more evidence is needed to evaluate the effectiveness as it seems to depend on the type of infection (fungus vs. yeast).¹⁴