Trichophyton rubrum and one case of Epidermophyton floccosum infections. At week 52, all dermatophytomas resolved with mean time to resolution at week 16. All cultures were negative and 65% achieved the primary endpoint of cure with <10% target nail involvement. There is also a case of dermatophytoma resistant to oral terbinafine that was successfully treated with efinaconazole 10% solution.58
Fingernail Onychomycosis
Onychomycosis involving the fingernails has been associated with poorest quality-of-life scores.59 Use of topical antifungals for the treatment of fingernail onychomycosis is significantly understudied, with only efinaconazole being cursorily assessed. To date, no randomized controlled clinical trials enrolled patients with fingernail onychomycosis. A Japanese study by Noguchi et al evaluated 10 adult patients with fingernail onychomycosis treated with efinaconazole 10% solution daily over a mean treatment duration of 38.7 weeks and found that 50% of subjects exhibited a complete cure.60 A case by Miller and Lipner reported success of efinaconazole 10% solution daily for 6 months in the treatment of fingernail onychomycosis in a patient with scleroderma.61 Further study of topical antifungals in fingernail onychomycosis is needed.
Skin of Color
Assessment of topical antifungals in skin of color, particularly Latin Americans, is lacking. Latino immigrant workers in the United States have higher rates of skin disease due to working and living conditions. Pichardo-Geisinger et al reported that one-third of Latino immigrants in rural western North Carolina were diagnosed with onychomycosis, and 23.5% had both onychomycosis and tinea pedis.62 Of all the topical antifungal agents, only efinaconazole has been reported to be effective. A subgroup analysis by Cook-Bolden and Lin of the 2 phase 3 studies revealed efinaconazole efficacy to be slightly but statistically significantly higher among Latino patients than non-Latinos.63 To date, there has been no investigation of topical antifungals in non-Latino skin of color subjects.
Diabetic Patients
Onychomycosis is highly prevalent in patients with diabetes, with one-third of diabetics being affected. This is of particular concern given the increased risk of concomitant bacterial infections and cellulitis in diabetic onychomycosis patients.25 Given the oral polypharmacy of many diabetic patients, oral antifungal treatment may often be contraindicated for these patients. Topical antifungal treatment in this patient population is desperately needed.
Diabetic Patients
Onychomycosis is highly prevalent in patients with diabetes, with one-third of diabetics being affected. This is of particular concern given the increased risk of concomitant bacterial infections and cellulitis in diabetic onychomycosis patients.25 Given the oral polypharmacy of many diabetic patients, oral antifungal treatment may often be contraindicated for these patients. Topical antifungal treatment in this patient population is desperately needed.
Efinaconazole is the only topical antifungal agent specifically studied in toenail onychomycosis in diabetic patients with a reported complete cure rate. A single-site single-arm study in 40 diabetic subjects by Shofler et al found efinaconazole 10% to be effective in toenail onychomycosis after 50 weeks and did not correlate with glycemic control.65 Approximately 52% achieved clinical improvement of >50% of the target toenail, with complete cure rate achieved in ~11% of subjects. Post-hoc analysis of phase 3 multicenter trials of efinaconazole considering only diabetic subjects revealed similar complete cure rates of 13.0% to 18.8%.66 Daily application of ciclopirox 8% nail lacquer for 48 weeks was also assessed in 49 adult diabetic patients with onychomycosis in a single open-label single-armed noncomparative study by Brenner et al.67 Treatment with ciclopirox resulted in mycologic cure in 54.3% compared with 58.33% from efinaconazole treatment. However, complete cure rate was not reported in that study. While no randomized placebo-controlled trials have been performed assessing specifically the effect of efinaconazole in toenail onychomycosis in diabetic patients, the current data is promising.
CONCLUSION
Onychomycosis remains a significant public health concern with a large economic burden. Choice of therapy along with compliance is critical for both clinical outcome, safety, and health care costs. Advances in topical therapeutics have resulted in 3 topical antifungals specifically approved for use in toenail onychomycosis: ciclopirox, tavaborole, and efinaconazole. Given their differing mechanisms of
