Comprehending the Potential of Topical Therapies for the Treatment of Onychomycosis

Onychomycosis is a frequently occurring fungal infection that affects the nails of the fingers and toes. Infection is caused by yeasts, dermatophytes, and nondermatophyte molds. Onychomycosis should be confirmed by mycology. Diagnosis can be made by various techniques, such as microscopy, fungal culture, potassium hydroxide, polymerase chain reaction, and histopathology. This review was undertaken to study the challenges associated with topical therapy of onychomycosis and techniques to overcome these challenges.

The search engines used for carrying out the literature review were PubMed, Google, Scopus, and Google Scholar. The search terms employed were "topical therapies for onychomycosis", "diagnosis of onychomycosis", and "challenges in the treatment of onychomycosis". The data related to topical treatments were compiled, and articles available in English language were only considered.

The main challenge associated with topical therapy was found to be the unique structure of the nails, hampering drug penetration to the infection site and inducing fungal drug resistance. Conventional treatment methods, as well as novel techniques developed for topical therapy, like microporation, ionotophoresis, laser, and photodynamic therapy, have also been explored. Oral antifungals are most commonly used for moderate to severe onychomycosis as they provide greater cure rates, whereas topical application of antifungals is advocated for mild to moderate infections as it possesses a better safety profile. Efinaconazole solution (10%), tavaborole solution (5%), and ciclopirox nail lacquer (8%) for topical use are accepted by the Food and Drug Administration (FDA) for the management of onychomycosis. Laser treatment is approved in the United States for the short-term improvement of clear nails in fungal infections, but the clinical outcomes have not yet reached optimal levels.

Topical therapy can be considered a treatment option for mild to moderate onychomycosis, even though effective delivery of the drug is restricted by the nail's barrier properties. However, further clinical studies are required to establish their long-term efficacy.