Are topical and device-based treatments effective in people with fungal infections of the toenails?

Review question

We reviewed evidence about the effect of topical and device-based treatments for fungal infections of the toenails (toenail onychomycosis) when compared against each other, placebo (an identical but inactive treatment), vehicle (inactive ingredients that help deliver an active treatment), or no treatment. We assessed adults, whose infection was diagnosed based on studying nail samples.

Background

Toenail onychomycosis causes pain, discomfort, and disfigurement. Topical and device-based treatments can have less likelihood of drug interactions or side effects than oral drugs. Antifungal medications are either fungistatic (inhibiting fungal growth) or fungicidal (killing fungal pathogens). The shared goal of devices (e.g. laser, photodynamic therapy) is fungus destruction.

Study characteristics

In searches up to May 2019, we found 56 studies including 12,501 men or women (average age: 27 to 68 years) who had mainly mild-to-moderate toenail onychomycosis. Onychomycosis duration was under-reported, but varied from months to years. Approximately 63% of the studies assessed onychomycosis caused by dermatophytes (fungi). Most studies lasted 48 to 52 weeks and were conducted in an outpatient setting. The studies used either device-based or topical treatments, including lacquers and creams, alone or in combination, compared to each other, to no treatment, to vehicle, or to placebo.

Key results

For the following key results, treatment lasted 36 or 48 weeks, and outcomes were measured at 40 to 52 weeks (side effects were measured throughout the study).

Compared to vehicle (no treatment), efinaconazole 10% topical solution is better at achieving complete cure (i.e. normal-looking nail coupled with fungus elimination determined using laboratory methods) (high-quality evidence). Tavaborole 5% solution (when compared to vehicle) and P-3051 (ciclopirox 8% hydrolacquer) (when compared to two other treatments: ciclopirox 8% lacquer or amorolfine 5%) are probably better at achieving this outcome (both moderate-quality evidence). Ciclopirox 8% lacquer may lead to higher complete cure rates than vehicle, but rates are low (not all patients can be expected to achieve complete cure) (low-quality evidence).

Ciclopirox 8% lacquer and efinaconazole 10% are probably more effective at eliminating the fungus (mycological cure) than vehicle, but for P-3051 (ciclopirox 8% hydrolacquer) there is probably little or no difference compared to the two comparator treatments (all moderate-quality evidence). Tavaborole 5% improves mycological cure compared to vehicle (high-quality evidence).

We found no evidence of a difference in side effects, including redness, rash, and burning, between P-3051 (ciclopirox 8% hydrolacquer) and the two other treatments (low-quality evidence), and ciclopirox 8% lacquer may increase side effects, including application-site reactions, rashes, and changes in the nail compared with vehicle, although treatment effects vary, so it is possible that it may actually make little or no difference (low-quality evidence). Compared to vehicle, participants were slightly more likely to experience side effects (commonly dermatitis and fluid-filled sacs) with efinaconazole 10% (high-quality evidence) and probably more likely to experience side effects with tavaborole 5% (commonly, application-site reactions, such as dermatitis, redness, and pain) (moderate-quality evidence).

We are uncertain of the effect of luliconazole 5% on complete cure when compared to vehicle (very low-quality evidence); there may be little or no difference between these groups in side effects (dry skin, eczema, and thickening of the skin were commonly reported, but improved after stopping treatment), and luliconazole 5% solution might increase mycological cure; however, the effects of this treatment vary, so it is possible that it may actually make little or no difference to mycological cure (both low-quality evidence).

Three studies compared laser to no treatment or sham treatment, and there may be little or no difference in mycological cure (low-quality evidence). Complete cure was not measured, and we are uncertain if there is a difference in side effects between groups (very low-quality evidence).

Efinaconazole 10% solution is more effective in achieving clinical cure than vehicle (high-quality evidence); none of the other key comparisons measured this outcome.

Quality of the evidence

We base our conclusions on varied evidence quality. For complete cure, mycological cure, and side effects, quality ranged from low to high, with very low-quality evidence found for three key results.

Many studies were small, had design issues, and did not directly compare therapies. No studies reported quality of life.

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.

Read the full abstract...
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 strategy: 

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.

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