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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.

Safety and efficacy of tinea pedis and onychomycosis treatment in people with diabetes: a systematic review.

BACKGROUND: Effective treatment of tinea pedis and onychomycosis is crucial for patients with diabetes as these infections may lead to foot ulcers and secondary bacterial infections resulting in eventual lower limb amputation. Although numerous studies have assessed the effectiveness of antifungal drug and treatment regimens, most exclude patients with diabetes and examine otherwise healthy individuals. While these studies are useful, results cannot necessarily be extrapolated to patients with diabetes. The purpose of this study was to therefore identify the best evidence-based treatment interventions for tinea pedis or onychomycosis in people with diabetes.

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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 takes time to get rid of brittle, discolored, or thickened nails. Local treatment using nail polish can take up to a year. Tablets take effect more quickly, but have more side effects.

Nail fungus: Polish, cream or tablets?

Nail fungus can be very persistent. Topical treatment with nail polish may last as long as one year. Tablets for treating fungal nail infections usually have to be taken for several weeks or months. They are much more effective than topical treatments, but they have more side effects.Crumbly nails and a whitish-yellowish to brownish discoloration are typical signs of nail fungus. The nails may also become thicker and change shape. The affected part of the nail can become detached from the nail bed. Treatment options for nail fungus include nail polishes and creams as well as tablets. Nail polishes and creams are available in pharmacies without a prescription.

More about Onychomycosis

Photo of an adult

Also called: Toenail fungal infection

Other terms to know:
Fungal Infections, Fungus, Toenail

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