Topical therapy for toenail onychomycosis: an evidence-based review

Managing toenail onychomycosis with topical treatments is challenging. It is difficult for topical medication to penetrate the nail plate, and this is reflected in lower cure rates with topical treatment than with oral treatment. However, oral medications may not be suitable for some patients, because of drug interactions; therefore, topical treatments are critical in managing the disease in certain patient populations.

This paper reviews the quality and content of the scientific literature on topical treatments for toenail onychomycosis.

PubMed, Ovid (Medline and Embase), Scopus, Cochrane library, and clinicaltrials.gov databases were searched for original clinical reports of topical monotherapy for microscopy and/or culture-confirmed toenail onychomycosis in adults. Studies were evaluated using an onychomycosis study quality scale, which was based on the CONSORT guidelines.

Twenty-five publications (28 studies) were identified and met the inclusion criteria. Thirteen studies scored high ratings on the quality scale. These were randomized controlled trials or randomized comparative trials. Low-quality studies were nonrandomized, open studies that prevented statistical analysis. Most studies reported clinical and mycological cure. The most variation was observed with reporting outcomes of clinical improvement. Amorolfine, ciclopirox, tavaborole, and efinaconazole produced clinical and mycological cure in patients with mild to moderate toenail onychomycosis (<50-65 % nail involvement), with efinaconazole showing the highest rates. Treatments were generally applied daily for 24-48 weeks, with longer treatment and follow-up showing better outcomes.

Topical treatment with amorolfine, ciclopirox, tavaborole, or efinaconazole is appropriate for cases of mild to moderate toenail onychomycosis due to dermatophyte or mixed dermatophyte/Candida infection.