Fungal Infections of Fingernails and Toenails

A fingernail or toenail infection that is caused by a fungus is called onychomycosis (say: “on-ee-koh-my-kÓ-sis”).  The infection is more likely in toenails than in fingernails.

This infection can make your nails thick and discolored.  Your nail may also become brittle or change shape.

Who gets fungal nail infections?

Anyone can get fungal nail infections.  These infections are more common in adults older than 60 years but they also occur in young adults.  They are especially common in people with diabetes or circulation problems.  Children hardly ever get fungal nail infections.

What causes fungal nail infections?

It may be hard to know where or how you got a fungal nail infection.  A warm, wet place is a good place for a fungus to grow.  If you often wear heavy work boots all day, you might be more likely to get a fungal infection in your toenails.  If your feet get warm and sweaty inside the boots, a fungus can grow around your toenails.  If you often walk barefoot in locker rooms, you can pick up a fungus from the warm, wet floors.

People whose hands are often wet (for example, dishwashers in restaurants and professional house cleaners), are more likely to get fungal fingernail infections.

Sometimes several people in a family get fungal infections in their nails.  Their immune systems may not be able to fight off the fungus infection, or they spread the infection by using the same towels.

How do I find out if I have a fungal nail infection?

If you think you have a fungal infection in your fingernails or toenails, see your doctor.  By looking carefully at your nails, your doctor might be able to tell if you have an infection.  

To be sure that the nail problem you have is a fungal infection, your doctor might scrape a little bit of tissue from a nail and send it to a lab.  It might be a few days to weeks before your doctor gets the results of the lab test.  The test can tell if you have a fungal infection or another kind of problem.

Approximately 50% of patients with thickened, deformed nails don’t have fungal infections.

How is a fungal nail infection treated?

Several medicines can treat a fungal nail infection.  Your doctor can help you decide about treatment.

You might need to take the medicine for 3 to 6 months, or longer.  It depends on where the infection is and how bad it is.

What can I do to take care of my nails?

Here are some things you can do to take care of your nails while you have a fungal nail infection:

  • Keep your nails cut short and file down any thick areas. 

  • Don’t use the same nail trimmer or file on healthy and infected nails.  If you have your nails professionally manicured, you should bring your own nail files and trimmers from home.

  • Wear waterproof gloves for wet work (like washing dishes or floors).  To protect your fingers, wear 100 percent cotton gloves for dry work.

  • Wear 100 percent cotton socks.  Change your socks when they are damp from sweat or if your feet get wet.  Put on clean, dry socks every day.  You can put over-the-counter antifungal foot powder inside your socks to help keep your feet dry.

  • Wear shoes with good support and a wide toe area. Don’t wear pointed shoes that press your toes together.

  • Avoid walking barefoot in public areas, such as locker rooms.