Kathi Valeii is a freelance writer covering the intersections of health, parenting, and social justice.

Adam H. Kaplan, DPM, is a podiatrist who has been in private practice for over 5 years in New Jersey and specializes in a wide scope of foot care.

Toenail fungal infections (onychomycosis) are a common toenail problem. An estimated 10% of the population is affected by nail fungus.

Toenail fungus causes discoloration, nail thickening, and nail cracking and breaking. It occurs when an overgrowth of fungus gets into your nail and causes an infection.

This article explains toenail fungus causes, symptoms, treatment, potential complications, and prevention steps. 

Microscopic organisms cause toenail fungus. You can come into contact with fungi that can cause an infection in various ways, including:

While anyone can get toenail fungus, some people are more susceptible, including:

The symptoms of toenail fungus are usually easy to spot. They include:

Toenail fungus is often mild and painless in the beginning. However, as the fungus grows, you may experience pain and difficulty wearing shoes. At later stages, a fungal infection is more resistant to treatment. Seek medical treatment at the first sign of a toenail fungal infection.

There are several approaches to treating toenail fungus, including oral, topical, and laser treatments. Often, which treatment you receive will depend on the severity of your infection.

Topical toenail fungus treatments are antifungal medicines that you apply directly to the nail. These medications are not the most effective treatment method; however, they can be a good option if the case is mild. The U.S. Food and Drug Administration (FDA) has approved the following topical treatments:

Amorolfine and ciclopirox are the most common topical nail fungus treatments. You apply them like nail polish daily for up to a year. However, since topical medications are less effective, especially in more moderate and severe cases, healthcare providers sometimes combine them with another treatment method, like oral medication.

Topical treatments keep new fungus from growing while the nail grows out. Therefore, this treatment can take a while—sometimes upward of a year or longer.

Oral medications are the frontline treatment for toenail fungus because they are the most effective. In addition, they work faster, often in just a few months. The following are FDA-approved oral nail fungus medications:

While these medications are effective, they can produce serious side effects, including liver and heart problems. Therefore, while you receive oral treatment, your healthcare provider will monitor you periodically by checking blood work with a CBC and LFT (liver function test). As long as your numbers are within normal limits, the medicine is safe to take.

Nail debridement (removal) may be necessary if you don't respond to or can't take other treatments. A healthcare provider may surgically remove your nail or apply a chemical to the nail to encourage it to fall off on its own.

Laser therapy may be a good option for people who can not tolerate medications and don't want to lose their toenails. With laser therapy, a healthcare provider uses a laser to apply heat to the toenail to kill the fungus and inhibit further fungal growth.

A study examined the effectiveness and safety of laser treatment for nail fungus. Researchers evaluated 35 articles, including 1,723 participants. The overall cure rate was 63% but was higher with a CO2 laser, which had a cure rate of 74%.

Researchers found that laser treatments are safe and effective. However, they can result in some pain and bleeding. Laser therapy may be an out-of-pocket expense for most people as it is usually not covered by insurance.

When you don't address toenail fungus early, it can develop into a more severe infection, which may result in ridding the toenail of fungus, loss of the toenail, or pain.

In addition, the medication used to treat nail fungus can cause complications, including heart and liver problems and anaphylaxis , a severe allergic reaction.

When taking medication, watch for signs of serious problems, including:

You can take simple steps to reduce your likelihood of getting a toenail fungal infection. They include:

If you notice a fungal infection, make an appointment to see a healthcare provider.

Toenail fungus is caused by microscopic organisms that get into your nail and cause an infection. Anyone can get toenail fungus, but it is more common in older adults and those with chronic health conditions. Symptoms include discolored, thickening, and brittle nails. You can prevent toenail fungus by ensuring your feet and footwear are properly dry, wearing flip-flops in locker rooms and public showers, sanitizing nail clippers, and more.

If your toenails are flaking, thick, or yellow, don't ignore them—a fungal infection may be brewing. Remember, the sooner you begin treatment, the better your outcome. Tell a healthcare provider if you have allergies, heart disease, kidney or liver problems, blood disorders, or are taking any medication, as this may affect your medications.

Some people use apple cider vinegar or essential oils like tea tree oil as home remedies for nail fungus treatment. However, there is not sufficient evidence that these treatments work. Instead, it's better to work with a healthcare provider to determine the best treatment.

Untreated toenail fungus can quickly become worse. Fungal infections do not go away on their own; they continue to grow and spread.

Toenail fungus can be complicated to treat. That's because fungal infections are stubborn, and the treatment process is lengthy. You must continue taking your medication and see a healthcare provider if you're not improving. You may need a different treatment approach.

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Westerberg DP, Voyack MJ. Onychomycosis: current trends in diagnosis and treatment. AFP. 2013;88(11):762-770.

Centers for Disease Control and Prevention. Fungal nail infections.

American Academy of Dermatology Association. Nail fungus: who gets and causes.

American Academy of Dermatology Association. Nail fungus: signs and symptoms.

American Academy of Dermatology Association. Nail fungus: diagnosis and treatment.

Tabara K, Szewczyk AE, Bienias W, et al. Amorolfine vs. ciclopirox - lacquers for the treatment of onychomycosis. Postepy Dermatol Alergol. 2015;32(1):40-45. doi:10.5114/pdia.2014.40968

Ma W, Si C, Kasyanju Carrero LM, et al. Laser treatment for onychomycosis: a systematic review and meta-analysis. Medicine (Baltimore). 2019;98(48):e17948. doi:10.1097/MD.0000000000017948

American Academy of Dermatology Association. Twelve ways to prevent another nail infection.

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