Fungal Nail Infection

Written by April Khan and Elly Dock | Published on August 15, 2012
Medically Reviewed by George Krucik, MD on August 15, 2012

Fungal Nail Infection


Fungal infections can affect any part of the body, from the skin to the eyes. Fungi are normally present in and around the body along with bacteria. When a fungus begins to overgrow, an infection can occur.

Onychomycosis (also called tinea unguium) is a fungal infection that affects the nails. Fungal infections normally develop over time, so any immediate difference in the way your nail looks or feels may be too subtle to notice at first.

There are many different causes of fungal nail infections, and each cause has a treatment of its own. Although many of the causes of onychomycosis are preventable, some risk factors increase the likelihood of developing it. You are more likely to develop a fungal nail infection if you:

  • have diabetes
  • have a disease that affects the blood vessels
  • are an older woman
  • wear artificial nails
  • swim in a public swimming pool
  • have a nail injury
  • have moist fingers or toes for an extended time
  • have a weakened immune system
  • wear closed shoes, such as tennis shoes or boots

According to the University of California Student Health and Counseling Services, fungal infections affect toenails more commonly than fingernails.

Fungal nail infections are treatable in most cases; however, the fungus can return after treatment or cause future complications.

Why Does It Develop?

A fungal nail infection occurs from the overgrowth of fungi in, under, or on the nail. Fungi thrive in warm, moist environments, so this type of environment can cause them to naturally overpopulate. The same fungi that cause jock itch, athlete’s foot, and ringworm can cause infection in the nails.

Fungi that are already present in or on your body can cause nail infections. If you have come in contact with someone else who has a fungal infection, it may have spread to you. Because fungi prefer damp, dark conditions, fungal infections occur more often on the toenails than the fingernails. When your feet are inside shoes, it can create a dark and moist environment for fungi to thrive.

If you get a manicure or pedicure at a nail salon, be sure to ask how and how often the staff disinfects their tools. Tools, such as emery boards and nail clippers, can spread fungal infections from person to person if they are not sanitized.

Who Is at Risk for Fungal Infections?

Nail infections occur more often in men than in women, and the infections are found more often in adults than in children. If you have family members who often get these types of fungal infections, you are more likely to get them as well.

The elderly are at the highest risk for getting fungal infections of the nails because they have poorer circulation and their nails grow more slowly and thicken as they age. If a person has poor circulation, a compromised immune system, or skin injuries around the nails, it can put him or her at greater risk for nail infections.

What Does It Look Like?

A fungal infection of the nail may affect part of the nail, the entire nail, or several nails.

Visible Signs

Visible fungal nail infection signs include:

  • scaling under the nail (subungual hyperkeratosis)
  • white or yellow streak on the nail (lateral onychomycosis)
  • crumbling corner or tip of the nail (distal onychomycosis)
  • flaking white areas on the nail’s surface (may include pits in the nail)
  • yellow spots at the bottom of the nail (proximal onychomycosis )
  • loss of the nail

Common Signs

Common fungal nail infection signs include:

  • a distorted nail
  • an odor coming from the infected nail
  • a brittle or thickened nail

How Do I Know If I Have a Fungal Nail Infection?

Because other infections can affect the nail and mimic symptoms of fungal nail infection, the only way to confirm a diagnosis is to see a doctor. He or she will take a scraping of the nail and look under a microscope for signs of a fungus. In some cases, your doctor may have to send the scraping away for lab analysis and identification.

How Is a Fungal Nail Infection Treated?

Usually, over-the-counter products are not recommended to treat nail infections because they do not provide reliable results. Instead, your doctor may prescribe an oral antifungal medication, such as:

  • terbinafine
  • itraconazole
  • fluconazole
  • griseofulvin

You may use other antifungal treatments, such as antifungal nail lacquer or topical solutions. These treatments are brushed onto the nail in the same way that one would apply nail polish. Depending on the type of fungus causing the infection, as well as the extent of the infection, you may have to use these medications for several months. Topical solutions are not generally effective in curing toenail fungal infections.

Treatment isn’t guaranteed to rid your body of the fungal infection completely. In almost half of cases, the fungal nail infection will return.

Tips to Prevent Fungal Nail Infections

Making a few simple lifestyle changes can help prevent a fungal infection of the nails. Taking good care of your nails by keeping them well trimmed and clean is a good way to prevent infections from taking root. You should also avoid injuring the skin around your nails. If you are going to have damp or wet hands for an extended period, you may want to wear rubber gloves.

Other prevention tips include:

  • using antifungal sprays or powders regularly
  • washing your hands after touching infected nails
  • dry your feet well after showering especially between the toes
  • getting manicures or pedicures from trustworthy salons
  • using your own items for manicures or pedicures
  • wearing socks that minimize moisture
  • avoiding being barefoot in public places
  • reducing your use of artificial nails and nail polish

Long-Term Outlook and Future Health Complications

For some people, a fungal infection of the nails can be difficult to cure. It is estimated that medication eliminates fungus in only about 50 percent of patients. The nail infection cannot be considered cured until a new nail, free from infection, has grown in. Although this indicates that the nail is no longer infected, it is possible for the fungal infection to return. In severe cases, there may be permanent damage to your nail, and it may have to be removed.

The main complications of a fungal nail infection are:

  • a resurgence of the infection
  • a permanent loss of the affected nail
  • discoloration of the infected nail
  • the spread of infection to other areas of the body and possibly the bloodstream
  • the development of bacterial skin infection (cellulitis)

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