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Onychomycosis (Toenail Fungus)

Fungal infection of a fingernail or toenail.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

About Toenail Fungus

If your nails become brittle or change color, it might be caused by a fungal nail infection. The big toenails are often affected. Nail fungus is much less common in the fingernails.

Fungal nail infections are very persistent. Because our toenails only grow slowly, treatment generally takes a long time and requires patience. It can take several months until treatment is successful.


A whitish-yellowish or brownish discoloration of the nails is a sign of nail fungus. The nails may become brittle, thicker and change shape. Sometimes they are also painful. The affected part of the nail can detach from the nail bed. Nail fungus is also referred to as "onychomycosis."

The big toenails are particularly affected by nail fungus. In the vast majority of people, the fungus develops at the front or side edge of the nail. It is less common for the infection to spread from the nail root. This kind of infection is most common in people with a severely weakened immune system, possibly following a serious illness. It might also occur after an organ transplantation because people have to take medication that suppresses the immune system... Read more about Onychomycosis

What works? Research summarized

Evidence reviews

Systemic antifungals to treat onychomycosis in children: a systematic review

Because of the low prevalence of onychomycosis in children, little is known about the efficacy and safety of systemic antifungals in this population. PubMed and Embase databases and the references of related publications were searched in March 2012 for clinical trials (CTs), retrospective analyses (RAs), and case reports (CRs) on the use of systemic antifungals for onychomycosis in children (<18 years). Twenty-six studies (5 CTs, 3 RAs, and 18 CRs) were published between 1976 and 2011. Most of these studies reported the use of systemic terbinafine and itraconazole for the treatment of onychomycosis in children. Therapy with systemic antifungals alone in children ages 1 to 17 years resulted in a complete cure rate of 70.8% (n = 151), whereas combined systemic and topical antifungal therapy in one infant and 19 children age 8 and older resulted in a complete cure rate of 80.0% (n = 20). The efficacy and safety profiles of terbinafine, itraconazole, griseofulvin, and fluconazole in children were similar to those previously reported for adults. In conclusion, based on the little information available on onychomycosis in children, systemic antifungal therapies in children are safe and cure rates are similar to the rates achieved in adults.

A meta-analysis comparing long-term recurrences of toenail onychomycosis after successful treatment with terbinafine versus itraconazole

As the most frequently used systemic antifungal agents for onychomycosis, terbinafine and itraconazole have both proved to have the conditions of recurrence in various degrees during follow-up period after end of therapy; very little is known about their comparative recurrences after long-term follow-up. We conducted a meta-analysis of available trials to compare the long-term recurrences of toenail onychomycosis after successful treatment with terbinafine versus itraconazole. Meta-analysis was performed by the Review Manager version 5.0.25. Risk ratio and 95% confidence intervals were calculated by the fixed effect model. Five trials and total 251 eligible patients were included in this meta-analysis. The combined risk ratio of the meta-analysis comparing terbinafine with itraconazole for mycological recurrence rate was 0.44 (95% CI 0.29-0.66), which suggests that itraconazole therapy is more likely to produce mycological recurrence compared with terbinafine therapy.

The effectiveness of lasers in the treatment of onychomycosis: a systematic review

BACKGROUND: Onychomycosis is a common nail pathology which has proven to be a treatment challenge to healthcare professionals. Antifungal drugs have been the mainstay of therapy for many years. Recently, laser technologies have been introduced as a treatment for onychomycosis avoiding the disadvantages of systemic and topical drug therapies, offering a rapid treatment for an often persistent nail condition. The purpose of this study was to review published evidence regarding the effectiveness of laser technologies in the treatment of onychomycosis.

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Summaries for consumers

Creams, lotions and gels (topical treatments) for fungal infections of the skin and nails of the foot

We found lots of evidence to show fungal skin infections of the skin of the feet (athlete's foot or tinea pedis) are effectively managed by over the counter topical antifungal creams, lotions and gels. The most effective topical agent was terbinafine. Other topical agents such as azoles, ciclopiroxolamine, butenafine, tolnaftate and undecanoate were also effective in curing athlete's foot.

Nail fungus: Overview

Nail fungus is very common. Experts think that it often develops from untreated athlete's foot. It then takes a while to get rid of the brittle, discolored or thickened nails. Topical treatment with nail polish may take up to one year. Tablets work faster, but they have more side effects too.

What is the best medication for a fungal infection of the toenail?

We aimed to find out which medications, taken by mouth for at least six weeks, are the most effective at curing fungal infection of the toenail, a condition that is known as onychomycosis, in people of any age. We compared these medications to each other or placebo (an inactive drug or treatment).

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More about Onychomycosis

Photo of an adult

Also called: Toenail fungal infection

Other terms to know:
Fungal Infections, Fungus, Toenail

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