Definition of Fungal nail infection:

Fungal nail infection is an infection of the nails by a fungus.

Causes, incidence, and risk factors:

The body normally hosts a variety of 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:

• Cutaneous candidiasis
• Diaper rash
• Oral thrush
• Some cases of genital rashes

Fungal nail infections are most often seen in adults. They often follow fungal infection of the feet. 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. The fungi that cause them thrive in warm, moist areas.

The following increase the risk of a fungal infection:

• Getting minor skin or nail injuries
• Having moist skin for a long time
• Wearing closed-in footwear