What Are Fungal Nail Infections?

Don’t be embarrassed if you have toenail or fingernail fungus. It’s way more common than you think.

Fungi are tiny organisms you can only see through a microscope. There are many different types that can cause a nail infection. Sometimes they live on your skin and don’t make any trouble. But if you have a lot in one area, you might get infected.


Nail fungus -- its formal name is onychomycosis -- is a lot like athlete’s foot. But instead of affecting the skin on the bottom of your feet or between your toes, it invades your nails.

Since fungus thrives in dark, warm places, your toenails are more likely to be affected than your fingernails. Your toes also have less blood flow than your fingers, which makes it harder for your body to pick up on and prevent an infection.

Men are more likely to get fungal infections than women. Older people or those who have a weak immune system or ongoing (chronic) health problems like diabetes are also at higher risk.

Another way to set yourself up for an infection is wearing shoes that make your feet hot and sweaty. You’re also more likely to pick up a fungus when you don’t keep your feet clean and dry.

Walking barefoot through gym showers, swimming pools, and locker rooms can also increase your chances of infection. These are places where fungus spreads easily. If someone you live with has a fungal infection, you can also catch it from them.

And if you already have athlete’s foot, there is a chance that the fungus can spread to your nails.


At first, you may only see a white or yellow spot under your nail. Over time, this spreads and can turn your whole nail white, yellow, green or black.

Your nail may thicken and could be hard to trim. Many people notice that their nail starts to curl up or down or loosens from the nail bed. Or it could become brittle and crumble when you touch it.

It’s easy to ignore fungal nail infections at first, since you may not have any pain. But if left untreated, it can hurt to put any pressure on the area. If an infection gets bad enough, it can even become hard to walk.


Prevention and Treatment

It’s a good idea to wash your hands and feet often. Use soap, and make sure you get between your fingers and toes.

Keep your fingernails and toenails short and trimmed straight across.

Wear socks that wick away (absorb) moisture. If your feet sweat a lot, change your socks once or twice a day, or take off your shoes and let your feet cool when you have the chance.

Use antifungal powder or spray on your feet as well as in your shoes. Throw away old pairs of closed-toe shoes since fungi might be living in them.

If you get manicures at nail salons, visit only the ones that disinfect tools after each client. You can also bring your own file and clippers from home. Ask that your cuticles not be cut, since this can cause tiny breaks in the skin that let germs in.

Don’t share towels if someone else in your family has nail fungus. This will pass around the infection.

See your doctor if you think you have nail fungus. You may need a prescription to treat it, whether that means taking a medicine by mouth or using a special cream. In severe cases, your nail may need to be removed so a healthy new one can grow in its place. Doctors can also use lasers to treat nail fungus.

WebMD Medical Reference Reviewed by Stephanie S. Gardner, MD on March 05, 2020



American Academy of Family Physicians: “Nail Fungal Infections.”

American Family Physician: “Onychomycosis: Current Trends in Diagnosis and Treatment.”

National Health Service (U.K.): “Fungal Nail Infection.”

Mayo Clinic: “Nail Fungus.”

Cleveland Clinic: “How You Can Stop Foot and Toenail Fungus In Its Tracks.”

American Podiatric Medical Association: “Toenail Fungus.”

CDC: “Fungal Nail Infections.”

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