Types of Toenail Fungus: Pictures, Symptoms, and Treatment

Toenail fungus, also called onychomycosis or tinea unguium, is a fungal infection that can change the appearance of your toenails. They’re quite common, affecting up to 14% of people.

While fungal nail infections aren’t a serious health problem, they can sometimes cause pain. More often, though, they’re a cosmetic problem, as the toenail may become thick, discolored, or cracked.

This article will help you see what kind of toenail fungus you might have, who’s especially susceptible to toenail fungus, and whether you may be dealing with a different type of condition.

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You can pick up a toenail fungus from your environment. They often get in through small cracks in the nail or the skin around it.

The fungus may infect one nail or multiple nails and the surrounding skin. Each type has its own signs, symptoms, causes, and appearance.

Illustration by Julie Bang for Verywell Health

The most common type of toenail fungus is called subungual onychomycosis. It may affect the tip or sides of the nail. Look for:

The fungus, often Trichophyton rubrum, typically invades the nail bed and the underside of the nail plate. It then moves toward the base of the nail.

Less often, the infection begins at the base of the nail. This area then thickens and becomes discolored. This is associated with a compromised immune system, especially human immunodeficiency virus (HIV).

"Sub" means "under," and "ungual" refers to a fingernail or toenail. Thus, "subungual" means "under the nail."

White superficial onychomycosis is caused by a variety of fungi that invade the top layers of the toenail. It creates symptoms on the surface of the nail that include:

The most common cause of white superficial onychomycosis is the fungus Trichophyton mentagrophytes.

Candida (yeast) onychomycosis is most common in people who:

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Symptoms include:

This type of infection is especially common in agricultural workers due to exposure to wet environments, mud, and animal waste.

Anyone can develop a fungal toenail infection. But you may be more likely to develop it if you have:

They also grow more likely with age.

If a bacterial infection occurs along with your fungal infection, it can cause serious illness. Diabetes or a compromised immune system may increase this risk.

Toenail fungus can be difficult to clear up, and it usually doesn’t go away without treatment. You’re more likely to be successful if you start toenail fungus treatments right away.

You’ll know the treatment is working when you see healthy growth at the base of the nail.

If you have a very mild fungus, you may be able to keep it from getting worse by:

Keep in mind that this is a temporary measure and not a solution. Even if it seems to go away, the fungus is likely to come back. It’s best to make an appointment with a healthcare provider for a proper diagnosis and treatment.

Antifungal nail creams are widely available in drug stores and online. You may want to ask your healthcare provider or pharmacist to recommend a product, as not all of them are proven effective.

You might also want to use a nail-softening cream, which can make the infected areas easier to scrape off.

It may help to disinfect your socks and the insides of your shoes to ensure they’re not reintroducing the fungus when you wear them.

Prescription-strength topical antifungal medications are a common treatment option for toenail fungal infections. Topical medications that are approved by the Food and Drug Administration (FDA) include:

Side effects of topical agents can include:

Prescription oral (by mouth) antifungal medications may be used for a laboratory-confirmed toenail fungus. The most common treatment is a 12-week course of a drug called terbinafine.

However, some research suggests fungal infections can become resistant to terbinafine, so let your healthcare provider know if treatment doesn’t seem to be working.

For Candida infections, common drugs include:

Side effects of oral antifungal medications can include:

It’s also common to combine oral and topical treatments.

More and more, experts are urging healthcare providers to get a laboratory diagnosis before they start treatment in a patient. That way, they can start you on the proper treatment as soon as possible.

It may take several months or even a year for your fungal infection to clear up.

In the case of a severe and painfully malformed nail, your healthcare provider may suggest removing the entire nail permanently. This is a minor procedure that’s usually done with a local anesthetic to numb the area.

An ongoing fungal infection can spread from your toenail to other places, or to your nails from somewhere else. If you have or suspect a toenail fungus, take swift action to keep the problem from becoming worse.

Not all conditions that affect your toenail are fungal infections. Other conditions that can resemble a toenail fungus are:

Seeing a healthcare provider is the best way to determine what’s causing your toenail symptoms and find the right treatments.

Yes, toenail fungus is contagious. Just as it can spread to other nails or skin, it can also spread to other people.

You may catch or spread toenail fungus in the shower—including at the gym—or through practices such as sharing toenail clippers or shoes. This means that preventive measures are especially important when you have a fungal infection.

You can take steps to prevent toenail fungus, such as:

If you get pedicures, be sure to choose a clean, licensed salon. Ensure they sterilize all instruments before using them on you. You may also be able to bring your own supplies, but if they’ve been used, disinfect them first.

Both toenails and fingernails can develop fungal infections. However, it’s more common in toenails.

You should see a healthcare provider such as a podiatrist for a toenail fungus if you notice your toenails are:

You may need more aggressive treatment if:

Toenail fungal infections are common and can be difficult to treat. You may be prone to them if you have diabetes or a weakened immune system. Symptoms may include thickening, discoloration (white or yellow), crumbling, lifting, and spreading to the skin around the nail.

Treatment may involve some combination of over-the-counter products, prescription-strength topical treatments, and oral antifungal medications. You can prevent the spread of fungal toenail infections by keeping your feet clean and dry, wearing flip-flops in public showers, and sterilizing pedicure instruments after using them.

Many conditions cause similar symptoms. See your healthcare provider if you notice concerning changes in your toenails.

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

American Academy of Dermatology Association. What is nail psoriasis, and how can I treat it?

American Academy of Dermatology Association. How to check your nails for melanoma.

MedlinePlus. Darier disease.

National Organization for Rare Disorders. Yellow nail syndrome.

National Institutes of Health, National Institute of Arthritis and Musculoskeletal and Skin Diseases. Alopecia areata.

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

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By Adrienne DellwoAdrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic.