Onychomycosis: a review

Abstract

Onychomycosis is a fungal infection of the nail, causing discoloration and thickening of the affected nail plate, and is the most common nail infection worldwide. Onychomycosis was initially thought to be predominantly caused by dermatophytes; however, new research has revealed that mixed infections and those caused by non‐dermatophyte moulds (NDMs) are more prevalent than previously thought, especially in warmer climates. Microscopy and fungal culture are the gold standard techniques for onychomycosis diagnosis, but high false‐negative rates have pushed for more accurate methods, such as histology and PCR. As NDMs are skin and laboratory contaminants, their presence as an infectious agent requires multiple confirmations and repeated sampling. There are several treatment options available, including oral antifungals, topicals and devices. Oral antifungals have higher cure rates and shorter treatment periods than topical treatments, but have adverse side effects such as hepatotoxicity and drug interactions. Terbinafine, itraconazole and fluconazole are most commonly used, with new oral antifungals such as fosravuconazole being evaluated. Topical treatments, such as efinaconazole, tavaborole, ciclopirox and amorolfine have less serious side effects, but also have generally lower cure rates and much longer treatment regimens. New topical formulations are being investigated as faster‐acting alternatives to the currently available topical treatments. Devices such as lasers have shown promise in improving the cosmetic appearance of the nail, but due to a high variation of study methods and definitions of cure, their effectiveness for onychomycosis has yet to be sufficiently proven. Recurrence rates for onychomycosis are high; once infected, patients should seek medical treatment as soon as possible and sanitize their shoes and socks. Prophylactic application of topicals and avoiding walking barefoot in public places may help prevent recurrence.

Labeled use of efinaconazole topical solution 10% in treating onychomycosis in children and a review of the management of pediatric onychomycosis

“…25 It is therefore important to treat the tinea pedis with an effective agent when treating the toenails with a topical solution. 3,13 With both ciclopirox 8% nail lacquer topical solution 26 and efinaconazole topical solution 10% 27 it has been observed that the treatment of tinea pedis results in better response to the topical nail solution being used to treat the onychomycosis. Additionally, if the parents or close contacts have onychomycosis or tinea pedis treatment should be considered.…”

“…The prevalence of onychomycosis increases with age and is thus more commonly observed in individuals over 60 years of age (40%) and less frequently in children and infants (0.35%-5.5%). 1,3 In North America, the overall prevalence of onychomycosis in children below 18 years of age was 0.44% from a prospective, multicenter survey. 4 Efinaconazole topical solution, 10% is a triazole that was approved by Health Canada in 2013 and the US Food and Drug Administration (FDA) in 2014 for the treatment of toenail onychomycosis in adults.…”

Google search trends in onychomycosis: Influences of flip flops and advertising

“…Onychomycosis is contagious, often spreading between household members. It can also be spread through the community by the shared use of public showers, saunas, or pools, where the warm, damp, and wet conditions favor fungal growth 6,9 …”

“…Oral antifungals are given by prescription for 6‐12 weeks and consist of terbinafine (Lamisil ® ), itraconazole, and fluconazole. While mycological cure rates (negative fungal culture and microscopy) are higher for oral therapies (47%‐70%), systemic side effects and drug‐drug interactions result in medical professionals and consumers searching for non‐systemic alternatives for mild‐to‐moderate severity cases of onychomycosis 6,15‐18 …”

“…Many topical antifungals are available without a prescription (ie, over‐the‐counter, OTC) and include efinaconazole (Jublia ® ), tavaborole (Kerydin ® ), ciclopirox (Penlac ® , Rejuvenail ® ), amorolfine (Curanail ® , Loceryl ® ), and bifonazole (Canesten ® Fungal Nail Treatment Set, cream). Compared to the systemic antifungal therapies, the topical antifungals have lower mycological cure rates, ranging from 29% to 60% 6,19‐24 . These lower mycological cure rates may be attributed in part to slow growth of new nail and difficulty in subungual penetration from the dorsal nail plate to the underlying nail bed.…”