When diagnosing onychomycosis, laboratory testing is used for confirmation after identifying at least one clinical sign of possible
onychomycosis (longitudinal ridging/splitting, onycholysis, subungual hyperkeratosis, nail plate thickening/crumbling, or nail discoloration). This is necessary because nail dystrophy has a broad differential diagnostic list with numerous mimickers such as psoriasis, lichen planus, and chronic trauma.53 For confirmatory testing, it is recommended to obtain subungual debris from the most proximal involvement, ideally with attached nail bed, using a nail elevator or 2 mm curette. Confirmatory tests performed on these samples include histopathology, fungal culture, periodic acid-Schiff (PAS) stain or Gomori methenamine silver (GMS) stain, and KOH with microscopy. Histopathology with PAS/GMS stains are also performed on nail clippings. In addition, Polymerase Chain Reaction (PCR) can be used to identify the fungal organism more rapidly than culture and with high sensitivity. However, PCR testing is currently prohibitive for general use due to its high cost.54
An interdisciplinary committee comprised of dermatologists, podiatrists, and a microbiologist published consensus guidelines in 2021 for the treatment of toenail onychomycosis.50 For healthy adult patients <65 years of age, topical efinaconazole monotherapy in 2021 for the treatment of toenail onychomycosis.50 For healthy adult patients <65 years of age, topical efinaconazole monotherapy is also recommended for patients with liver and kidney issues, pediatric patients, and patients on medications that may adversely interact with oral therapies. Oral therapy with or without topical is recommended for moderate-to-severe disease with terbinafine being first-line and onazole being second-line. Combinationtopical and oral therapy is recommended for adult patients >=65 years of age, with peripheral vascular disease, with diabetes, immunocompromised, and those who failed topical monotherapy.
An interdisciplinary committee comprised of dermatologists, podiatrists, and a microbiologist published consensus guidelines in 2021 for the treatment of toenail onychomycosis.50 For healthy adult patients <65 years of age, topical efinaconazole monotherapy in 2021 for the treatment of toenail onychomycosis.50 For healthy adult patients <65 years of age, topical efinaconazole monotherapy is also recommended for patients with liver and kidney issues, pediatric patients, and patients on medications that may adversely interact with oral therapies. Oral therapy with or without topical is recommended for moderate-to-severe disease with terbinafine being first-line and onazole being second-line. Combinationtopical and oral therapy is recommended for adult patients >=65 years of age, with peripheral vascular disease, with diabetes, immunocompromised, and those who failed topical monotherapy.
In the event of either topical or oral treatment failure, it is recommended to reassess and retest for confirmation of the original diagnosis of onychomycosis. For topical monotherapy failures, nail adjunctive nail debridement and oral therapy are suggested. For the specific case of terbinafine failure, it is recommended to send a sample for susceptibility testing after taking the patient off terbinafine treatment for one month. If susceptibility testing reveals a low minimal inhibitory concentration (MIC), then it is advised to undergo a second course of oral terbinafine therapy with adjunct topical therapy for maintenance, with a preference for efinaconazole given the higher rates of complete and mycologic cure vs other topical treatments. If MIC is high, then it is recommended to switch to fluconazole oral therapy with adjunctive topical therapy. For pregnant or lactating patients, there are no consensus recommendations at this time.
Efinaconazole 10% Solution in Unique Circumstances and Special Populations
Dermatophytomas
Dermatophytomas are biofilms of fungal collections that adhere to surfaces.55 These collections are circumscribed, dense, and generally
resistant to standard antimicrobials. In the nail, dermatophytomas appear as yellow/white streaks or patches in the subungual space.
They are less responsive to systemic antifungal therapy such as terbinafine and fluconazole, likely due to difficulties in accessing
and penetrating the fungal biofilm.56 Thus, a combination therapy approach is generally employed with both topical and oral agents. Given this difficulty in treatment, clinical trials assessing topical and oral antifungals have traditionally excluded patients with dermatophytomas.17,27
To date, only efinaconazole has been studied specifically in patients with dermatophytomas. While one study by Aly et al performed a posthoc analysis on the efficacy of tavaborole on phase 2 onychomycosis patients with dermatophytomas,57 no studies specifically recruited patients with dermatophytomas for study. Wang et al assessed the efficacy of efinaconazole 10% solution applied daily for 48 weeks in 19 patients specifically with dermatophytomas of the great toenail.56 Baseline dermatophytoma cultures showed
To date, only efinaconazole has been studied specifically in patients with dermatophytomas. While one study by Aly et al performed a posthoc analysis on the efficacy of tavaborole on phase 2 onychomycosis patients with dermatophytomas,57 no studies specifically recruited patients with dermatophytomas for study. Wang et al assessed the efficacy of efinaconazole 10% solution applied daily for 48 weeks in 19 patients specifically with dermatophytomas of the great toenail.56 Baseline dermatophytoma cultures showed
