Onychomycosis

Alternative names

Nails - fungal infection; Fungal nail infection; Infection - fungal - nails

Definition

This disease is an infection of the nails by a fungus.

Causes, incidence, and risk factors

The body normally hosts a variety of microorganisms, including bacteria and fungi. Some of these are useful to the body. Others may multiply rapidly and form infections. Fungi can live on the dead tissues of the hair, nails, and outer skin layers.

Fungal infections include mold-like fungi that cause:

• athlete's foot
  
• jock itch
  
• ringworm
  
• tinea capitis
  

Fungal infections also include yeast-like fungi (such as Candida). Candida yeast infections include:

• diaper rash
  
• oral thrush
  
• cutaneous candidiasis
  
• some cases of genital rashes
  

Fungal nail infections are most often seen in adults. They often follow fungal infection of the feet. Fungal nail infections may be difficult to treat and may recur often. Toenails are affected more often than fingernails.

People who frequent public swimming pools, gyms, or shower rooms; and people who perspire a great deal commonly have mold-like infections because the fungi that cause them thrive in warm, moist areas.

The risk of getting a fungal infection is increased by closed-in footwear, prolonged moist skin, and minor skin or nail injuries.

Symptoms

• Nail changes on one or more nails (usually toenails):
  o Brittle
  o Discolored
  o Loss of luster and shine
  o Thickening
  o Distorted nail shape
  o Crumbling of the nail
  o Debris under the nail
  o Loose (detached) nail
  

Signs and tests

Your doctor will suspect a fungal infection based on the appearance of the nails.

The diagnosis can be confirmed by scraping the nail for a culture or examining it under a microscope to identify the type of fungus.

Treatment

Creams and ointments are generally no help in treating onychomycosis. Recently, however, a nail lacquer (called Penlac) has been marketed and may be helpful in some patients.