Light Therapy Effectively Treats Onychomycosis and Promotes Healthy Nail Growth in Toenails with Severe Infections: A Longitudinal Cohort Study

Background: Onychomycosis is a stubborn fungal infection of the nail bed that impacts millions of people worldwide. Severe infections, such as those exhibiting deep dermatophytomas or total dystrophy, are particularly challenging to treat, and are often neglected in clinical studies of onychomycosis therapies. The purpose of this study was to evaluate the safety and efficacy of a novel light therapy suitable for severe cases of distal-lateral subungual onychomycosis. Methods: All infected nails received a photodisinfection regimen that entailed exposure of the whole dorsal foot surface to light, following application of a topical formula, as well as careful debridement to reduce hyperkeratosis. The protocol was administered every 2 weeks over 6 months. The length of clear healthy nail from the matrix was measured at baseline and after 6 months to evaluate new clear growth. Results: In total, 165 great toenails were treated in 101 patients (mean age: 61.0 ± 11.0 years, range 33–98); 153 of these nails (92.7%) had severe infections, including total dystrophy or dermatophytomas, the clinical forms most resistant to therapy. After 6 months, 120/165 nails (72.7%) showed at least a 3 mm increase in clear nail or total clearance, and 88 (53.3%) showed an increase ≥6 mm or clearance. The overall mean growth (±standard deviation) was 5.9 ± 4.5 mm, with the highest growth in the group with total dystrophy (6.6 ± 4.5 mm). No side effects were reported throughout the study. Conclusions: Light therapy is a safe and effective treatment for severe onychomycosis, including nails with total dystrophy and dermatophytomas.