Topical and device-based treatments for fungal infections of the toenails

BACKGROUND

Onychomycosis refers to fungal infections of the nail apparatus that may cause pain, discomfort, and disfigurement. This is an update of a Cochrane Review published in 2007; a substantial amount of new research warrants a review exclusively on toenails.

OBJECTIVES

To assess the clinical and mycological effects of topical drugs and device-based therapies for toenail onychomycosis.

SEARCH METHODS

We searched the following databases up to May 2019: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase and LILACS. We also searched five trials registers, and checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials.

SELECTION CRITERIA

Randomised controlled trials of topical and device-based therapies for onychomycosis in participants with toenail onychomycosis, confirmed by positive cultures, direct microscopy, or histological nail examination. Eligible comparators were placebo, vehicle, no treatment, or an active topical or device-based treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Primary outcomes were complete cure rate (normal-looking nail plus fungus elimination, determined with laboratory methods) and number of participants reporting treatment-related adverse events.

MAIN RESULTS

We included 56 studies (12,501 participants, average age: 27 to 68 years), with mainly mild-to-moderate onychomycosis without matrix involvement (where reported). Participants had more than one toenail affected. Most studies lasted 48 to 52 weeks; 23% reported disease duration (variable). Thirty-five studies specifically examined dermatophyte-caused onychomycosis. Forty-three studies were carried out in outpatient settings. Most studies assessed topical treatments, 9% devices, and 11% both. We rated three studies at low risk of bias across all domains. The most common high-risk domain was performance bias. We present results for key comparisons, where treatment duration was 36 or 48 weeks, and clinical outcomes were measured at 40 to 52 weeks. Based on two studies (460 participants), compared with vehicle, ciclopirox 8% lacquer may be more effective in achieving complete cure (risk ratio (RR) 9.29, 95% confidence interval (CI) 1.72 to 50.14; low-quality evidence) and is probably more effective in achieving mycological cure (RR 3.15, 95% CI 1.93 to 5.12; moderate-quality evidence). Ciclopirox lacquer may lead to increased adverse events, commonly application reactions, rashes, and nail alteration (e.g. colour, shape). However, the 95% CI indicates that ciclopirox lacquer may actually make little or no difference (RR 1.61, 95% CI 0.89 to 2.92; low-quality evidence). Efinaconazole 10% solution is more effective than vehicle in achieving complete cure (RR 3.54, 95% CI 2.24 to 5.60; 3 studies, 1716 participants) and clinical cure (RR 3.07, 95% CI 2.08 to 4.53; 2 studies, 1655 participants) (both high-quality evidence) and is probably more effective in achieving mycological cure (RR 2.31, 95% CI 1.08 to 4.94; 3 studies, 1716 participants; moderate-quality evidence). Risk of adverse events (such as dermatitis and vesicles) was slightly higher with efinaconazole (RR 1.10, 95% CI 1.01 to 1.20; 3 studies, 1701 participants; high-quality evidence). No other key comparison measured clinical cure. Based on two studies, compared with vehicle, tavaborole 5% solution is probably more effective in achieving complete cure (RR 7.40, 95% CI 2.71 to 20.24; 1198 participants), but probably has a higher risk of adverse events (application site reactions were most commonly reported) (RR 3.82, 95% CI 1.65 to 8.85; 1186 participants (both moderate-quality evidence)). Tavaborole improves mycological cure (RR 3.40, 95% CI 2.34 to 4.93; 1198 participants; high-quality evidence). Moderate-quality evidence from two studies (490 participants) indicates that P-3051 (ciclopirox 8% hydrolacquer) is probably more effective than the comparators ciclopirox 8% lacquer or amorolfine 5% in achieving complete cure (RR 2.43, 95% CI 1.32 to 4.48), but there is probably little or no difference between the treatments in achieving mycological cure (RR 1.08, 95% CI 0.85 to 1.37). We found no difference in the risk of adverse events (RR 0.60, 95% CI 0.19 to 1.92; 2 studies, 487 participants; low-quality evidence). The most common events were erythema, rash, and burning. Three studies (112 participants) compared 1064-nm Nd:YAG laser to no treatment or sham treatment. We are uncertain if there is a difference in adverse events (very low-quality evidence) (two studies; 85 participants). There may be little or no difference in mycological cure at 52 weeks (RR 1.04, 95% CI 0.59 to 1.85; 2 studies, 85 participants; low-quality evidence). Complete cure was not measured. One study (293 participants) compared luliconazole 5% solution to vehicle. We are uncertain whether luliconazole leads to higher rates of complete cure (very low-quality evidence). Low-quality evidence indicates there may be little or no difference in adverse events (RR 1.02, 95% CI 0.90 to 1.16) and there may be increased mycological cure with luliconazole; however, the 95% CI indicates that luliconazole may make little or no difference to mycological cure (RR 1.39, 95% CI 0.98 to 1.97). Commonly-reported adverse events were dry skin, paronychia, eczema, and hyperkeratosis, which improved or resolved post-treatment.

AUTHORS' CONCLUSIONS

Assessing complete cure, high-quality evidence supports the effectiveness of efinaconazole, moderate-quality evidence supports P-3051 (ciclopirox 8% hydrolacquer) and tavaborole, and low-quality evidence supports ciclopirox 8% lacquer. We are uncertain whether luliconazole 5% solution leads to complete cure (very low-quality evidence); this outcome was not measured by the 1064-nm Nd:YAG laser comparison. Although evidence supports topical treatments, complete cure rates with topical treatments are relatively low. We are uncertain if 1064-nm Nd:YAG laser increases adverse events compared with no treatment or sham treatment (very low-quality evidence). Low-quality evidence indicates that there is no difference in adverse events between P-3051 (ciclopirox hydrolacquer), luliconazole 5% solution, and their comparators. Ciclopirox 8% lacquer may increase adverse events (low-quality evidence). High- to moderate-quality evidence suggests increased adverse events with efinaconazole 10% solution or tavaborole 5% solution. We downgraded evidence for heterogeneity, lack of blinding, and small sample sizes. There is uncertainty about the effectiveness of device-based treatments, which were under-represented; 80% of studies assessed topical treatments, but we were unable to evaluate all of the currently relevant topical treatments. Future studies of topical and device-based therapies should be blinded, with patient-centred outcomes and an adequate sample size. They should specify the causative organism and directly compare treatments.

Global perspectives for the management of onychomycosis

Onychomycosis is a fungal nail infection caused by dermatophytes, nondermatophyte molds, and yeasts. This difficult-to-treat chronic infection has a tendency to relapse despite treatment. This paper aims to offer a global perspective on onychomycosis management from expert physicians from around the world. Overall, the majority of experts surveyed used systemic, topical, and combination treatments approved in their countries and monitored patients based on the product insert or government recommendations. Although the basics of treating onychomycosis were similar between countries, slight differences in onychomycosis management between countries were found. These differences were mainly due to different approaches to adjunctive therapy, rating the severity of disease and use of prophylaxis treatment. A global perspective on the treatment of onychomycosis provides a framework of success for the committed clinician with appreciation of how onychomycosis is managed worldwide.

Onychomycosis in the 21st Century: An Update on Diagnosis, Epidemiology, and Treatment

Onychomycosis accounts for 50% of all nail disease cases and is commonly caused by dermatophytes. Diabetes, human immunodeficiency virus, immunosuppression, obesity, smoking, and advancing age are predisposing factors of this fungal infection. Potassium hydroxide and culture are considered the current standard for diagnosing onychomycosis, revealing both fungal viability and species identification. Other diagnostic tests currently available include periodic acid-Schiff staining, polymerase chain reaction techniques, and fluorescent staining. Across 6 recently published epidemiology studies, the global prevalence of onychomycosis was estimated to be 5.5%, falling within the range of previously reported estimates (2%-8%). Newly approved onychomycosis treatments include efinaconazole, tavaborole, and laser therapy with lasers only approved to temporarily increase the amount of clear nail. Additional onychomycosis treatments being investigated include iontophoresis and photodynamic therapy with small open-label studies reported thus far. Preventative strategies, to help decrease recurrence and reinfection rates, include sanitisation of footwear and prophylactic topical antifungal agents.

Toenail Onychomycosis—A Canadian Approach With a New Transungual Treatment

Background:

Onychomycosis is a difficult-to-treat infection whose current treatment paradigm relies primarily on oral antifungals. The emergence of new topical drugs broadens the therapeutic options and prompts a re-evaluation of the current Canadian treatment strategy.

Objective:

To define a patient-centred Canadian treatment strategy for onychomycosis.

Methods:

An expert panel of doctors who treat onychomycosis was convened. A systematic review of the literature on treatments for onychomycosis was conducted. Based on the results, a survey was designed to determine a consensus treatment system.

Results:

First-line therapy should be selected based on nail plate involvement, with terbinafine for severe onychomycosis (>60% involvement), terbinafine or efinaconazole for moderate onychomycosis (20%-60% involvement), and efinaconazole for mild onychomycosis (<20% involvement). Comorbidities, patient preference and adherence, or nail thickness may result in the use of alternative oral or topical antifungals.

Conclusion:

These guidelines allow healthcare providers and patients to make informed choices about preventing and treating onychomycosis.

Management of Onychomycosis in Canada in 2014

Background

Onychomycosis has several clinical presentations and is caused by various infectious organisms.

Objective

To provide guidance for selection of appropriate treatment.

Methods

The literature on onychomycosis management was reviewed to generate an evidence-based decision tree.

Results and Conclusion

Several options are available: terbinafine, itraconazole, fluconazole, ciclopirox 8% nail lacquer, efinaconazole 10% nail solution, and laser therapy. Further studies on lasers are needed before use can be recommended. Nondermatophyte molds or mixed infection can be managed with terbinafine or itraconazole with or without topicals. Itraconazole, fluconazole, and efinaconazole can be used for Candida infection. For dermatophytes, topicals can be considered for mild to moderate onychomycosis. For moderate to severe cases, any oral monotherapy can be used; however, we suggest terbinafine if there is a possibility of a drug interaction. These recommendations can be applied for all ages, immune function, or metabolic status, but proper monitoring and contraindications should be taken into consideration.

Evaluation of PCR for the diagnosis of dermatophytes in nail specimens from patients with suspected onychomycosis

BACKGROUND

Conventional methods for detecting fungi in nail specimens are either nonspecific (microscopy) or insensitive (culture). Recently, PCR has been used to improve sensitivity in detecting the causative fungi in nail specimens from patients with suspected onychomycosis.

AIM

To compare the detection rates of PCR with those of microscopy (with potassium hydroxide; KOH) and culture for dermatophytes in nail specimens from patients with suspected onychomycosis.

METHODS

In total, 120 patients with clinically suspected onychomycosis were recruited, and using a topoisomerase II-based PCR, we compared the detection rate of dermatophytes for the three methods.

RESULTS

KOH microscopy, culture and PCR respectively yielded positive rates of 35 (29.2%), 12 (10%) and 48 (40%), and negative rates of 85 (70.8%), 108 (90%) and 72 (60%). Two culture-positive specimens were not detected by PCR, but PCR picked up 38 specimens missed by culture. Of the 35 specimens that were microscopy-positive, 12 grew dermatophytes and 23 nondermatophytes.

CONCLUSIONS

This study demonstrates that PCR has a higher positive and lower negative rate for detection of dermatophytes compared with KOH microscopy or culture. We suggest that PCR should be used as a complementary method for confirmation of clinically suspected dermatophytic onychomycosis.