Onychomycosis, or nail fungus, is the most common infection of the nails. It appears under the fingernail or toenail as a result of exposure to a warm, moist environment like sweaty shoes or shower floors. Nail fungus occurs more frequently in toenails because toenails are more often confined to dark, moist environments. Usually, the first sign of a nail fungus is a white or yellow spot under the nail. Left untreated, the nail fungus develops into thickened, brittle, damaged nails. The nails may split or crumble, or separate from the nail bed, a condition known as onycholysis, and the nail bed may become permanently damaged. Nail fungal infections are contagious and can spread among the nails or to skin in the adjacent area.

Risk factors for Nail Fungus

The most common risk factor for nail fungus is aging due to decreased circulation and the greater susceptibility to infection of thicker nails that are slower to grow. Other risk factors for nail fungus include:

  • Being male
  • Having a family history of nail fungus
  • Sweating a great deal
  • Walking barefoot in humid or moist surroundings
  • Having psoriasis or athlete's foot
  • Having a minor skin or nail injury
  • Being diabetic or having circulatory problems
  • Having a weakened immune system

Symptoms of Nail Fungus

The symptoms of nail fungus usually at first involve only an abnormal appearance of the nail but may then evolve into discomfort or pain. These symptoms include:

  • Thick or darkened nails
  • Brittle, split, ragged or crumbling nails
  • Nails with distorted shape
  • Dull, lusterless nails
  • Pain in the toes or fingertips
  • Nails that emit a slightly foul odor

Treatment of Nail Fungus

Because of the possibility of permanent damage, nail fungus should be treated promptly. Over-the-counter medications are widely available in the form of powders, ointment and anti-fungal nail polish. With treatment, healthy nails, free of the nail fungus, should grow out, replacing the diseased portions of nails. Positive results are normally visible within 1 to 2 weeks.

In more resistant cases, where over-the-counter medications are ineffective, stronger oral antifungal medications may be prescribed. In the latter case, complete healing may take several months. Oral medications for nail fungus may have serious side effects from skin rashes to liver damage, and so are not recommended for patients with liver disease, congestive heart failure or those who take certain medications. In severe cases, the nail may have to be removed for healing to be successful.

Complications of Nail Fungus

In most cases, nail fungus is not a serious problem, but for patients with diabetes or those with weakened immune systems, nail fungus may be dangerous. Patients with AIDS, leukemia or other cancers, or patients who have received organ transplants should be carefully monitored.

Additional Resources