What is a Fungal Nail Infection?

A fungal nail infection occurs when the underside of the nail, called the nail bed, becomes infected by a fungus. Fungal infections may first appear as a small white or yellow spot under the surface of the nail and spread to cover the entire nail bed. Fungal nail infections may cause the nail to fracture, crumble, or otherwise deteriorate. It can affect multiple fingers but rarely all of them at once.

If you have no existing major health complications, especially topical ones, fungal nail infections are not likely to cause serious problems. Treatment methods are available is the infection becomes unsightly, uncomfortable, painful, or otherwise interferes with your motor skills and daily life.

Causes of Fungal Nail Infections

A variety of fungi, yeasts, and molds can infect the nail bed, one of the most common being  tinea unguium. When a fungal infection spreads from the toenail to the foot or toes, the fungus is then classified as tinea pedis, more commonly known as athlete’s foot.

Fungi are microscopic organisms that thrive in close, damp environments and don’t need sunlight to survive. Some can cause illness and various ailments, and others have beneficial uses. Some important facts to know about fungi include:

  • They thrive in warm and damp environments like pools, showers, and locker rooms floors.
  • They infect your nails and skin through tiny, often microscopic cuts and openings around the nail bed.
  • They are more likely to be problematic if the hands and feet are often exposed to warm, damp environments.

Fungal nail infections are more likely to infect the toenails than the fingernails because the foot is often confined within the damp, warm interior of shoes, which make the perfect breeding grounds for fungi. Toes also get less circulation than fingers do, so it’s harder for the body’s immune system to reach and attack infections in the foot region.

Symptoms of Fungal Nail Infections

Fungal nail infections are normally easy to notice and are rarely painful. Common symptoms include:

  • Nail becomes white or yellow
  • Nail thickens noticeably
  • Nail become brittle, ragged, abnormal in shape, or dull
  • Nail begins to break easily, crumble, or deteriorate
  • Dull pain
  • Discoloration under the nail caused by fungal debris
  • Nail separates completely from the nail bed, a condition called onychomycosis
  • Unpleasant odor

When to see a doctor: Make an appointment with your doctor if self-care does not alleviate pain or take care of symptoms, especially if you have diabetes or other diseases that lower your immune system.

Treatment Options

A doctor or dermatologist can usually diagnose a fungal nail infection simply by looking at it and conducting a brief physical exam of the afflicted area. If necessary, your doctor may take a sample of the fungus and send it into a lab to be tested to rule out the presence of other common skin diseases, like psoriasis.


When left untreated, the fungal infection will not improve and may worsen. If over-the-counter medications, increased hygiene, and self-care methods do not work, other treatment options are available to eliminate or alleviate the symptoms of a fungal nail infection.



  • Oral antifungal drugs: Your doctor may prescribe an antifungal drug like Lamisil or Sporanox for a period of six to twelve weeks. These medications slowly replace the infected part of the nail, restore the health of the nail, and help the nail grow without infection. Potential side effects include liver complications and topical rashes, and these drugs are not recommended for people with congestive heart failure or preexisting liver problems.
  • Medicated nail polish: Your doctor may also prescribe a clear medicated nail polish called ciclopirox, or Penlac. The polish should be applied to the nail and surrounding skin in a thin layer once a day and, on the seventh day, removed all at once. This process can take up to a year of application to fully eliminate the fungal infection.
  • Medicated nail cream: A prescription antifungal cream may also help eliminate a fungal nail infection. The cream should be applied daily to the affected area after soaking. For best results, consider thinning the affected nail with a nail file before application; the thinner the nail, the easier the medication can reach the fungus under the surface of the nail.


Nail Removal

In cases where the fungal nail infection causes extreme pain or discomfort, complete removal of the affected nail may be the best option. The nail almost always grows back healthy, though it may take a period of a year or so for the new nail to grow in completely.


Light-Based and Laser Therapies

Carbon-dioxide laser therapy, which targets the fungus with a small but extremely powerful laser, has been proven to have significant success in curing fungal infections, especially when used in conjunction with daily applied medicated nail cream.



Fungal nail infections can be recurring and appear on different nails every time, so taking precautions against contracting the fungus again is always in your best interest.

  • Always wash and dry feet before bed.
  • Apply Vicks VapoRub. 56% of subjects in a fungal infection study saw significant or partial improvement in their condition after using this over-the-counter topical cream.
  • Change songs regularly to avoid dampness.
  • Do not share belongings that may come into contact with the fungus, like nail clippers, nail files, shoes, socks, or towels.
  • Trim, thin, and clean fingernails and toenails regularly.