Fungal Skin / Nail Infection

Alternative names: Nail Fungus.

Fungal infections are caused by microscopic organisms (fungi) that can live on the skin.  They can live on the dead tissues of the hair, nails, and outer skin layers.  Fungal infections include mold-like fungi (dermatophytes, which cause tinea infections) and yeast-like fungi (such as Candida).

There are several types of fungal infection.  These infections are generally named for the part of the body they affect.  Doctors commonly use the term tinea followed by the Latin name for the body part affected to identify the specific kind of infection.  As tinea grows, it will often spread out in a circle, leaving normal-appearing skin in the middle, which makes it look like a ring.  At the edge of the ring, the skin is lifted up by the irritation and looks red and scaly.  To some people, the infection looks like a "worm" is under the skin.  Because of the way it looks, tinea infection is often called "ringworm."

Examples include: athlete's foot (tinea pedis), jock itch (tinea cruris), body ringworm (tinea corporis), ringworm of the nails and toenails (tinea unguium), barber's itch (tinea barbae), ringworm of the hands (tinea manuum) and ringworm of the hair / scalp (tinea capitis).

Incidence; Causes and Development; Contributing Risk Factors

One of every five persons gets a fungal infection at some time.

Heat and humidity bring excess moisture and sweating to our bodies, creating the perfect environment for fungi to grow or fungal infections to develop.  Fungi tend to thrive in warm, moist places, such as between the toes, in the groin, under the breasts, and other parts of the body.  Cutaneous candidiasis is called Intertrigo when occurring under heavy skin folds.

You can get a fungal infection by touching a person who has one.  Some types of fungus live on damp surfaces such as the floors in public showers or locker rooms.  You can even catch a fungal infection from one of your pets.  Sometimes, the clothes we wear encourage fungi to develop, such as tight-fitting socks or close-fitting clothing.

Cutaneous candidiasis involves infection of the skin with candida.  It may involve almost any skin surface on the body, but usually occurs in warm, moist, creased areas (such as armpits and groins).  Cutaneous candidiasis is fairly common.  Candida is the most common cause of diaper rash in infants where it takes advantage of the warm moist condition beneath the diaper.  The most common fungus to cause these infections is candida albicans.

Candida can also cause infections of the nail, referred to as onychomycosis, and infections around the corners of the mouth, called angular cheilitis.  Oral thrush, a form of candida infection found on the mucous membranes of the mouth, may be a sign of HIV infection or other immunodeficiency disorders when it occurs in adults.  Infected individuals are not usually considered infectious to others, though in some settings transmission to immunocompromised hosts can occur.

Candida infection is particularly common in individuals with diabetes and in people who are obese.  Antibiotics and oral contraceptives increase the risk of cutaneous candidiasis.

Signs and Symptoms

Fungi are yeasts and molds that can infect and live in the topmost layer of the skin.  Fungal infections of the skin may affect the feet, groin, scalp, nails and other parts of the body.  Some fungal infections can be difficult to recognize because they may cause no symptoms or only cause slight redness and dryness.  Other fungal infections may cause itching, swelling, blistering and severe scaling or dry flaky skin.

Jock itch, or groin ringworm (tinea cruris), involves the skin of the groin and sometimes the upper thighs and buttocks.  It is most often seen in adult men, but may also occur in women.  Jock itch is not contagious.  In many cases, the source of the infection is the patient's own feet.  Jock itch and athlete's foot frequently occur together or in close succession.

Tinea cruris usually appears as scaly, ring-shaped patches with slightly raised borders that develop in the groin area and spread outward to one or both thighs, causing some redness and itching.  The skin of the scrotum and penis are usually spared, a feature that helps distinguish this condition from some other skin diseases with similar symptoms.

Treatment and Prevention

For Jock Itch, keep the groin clean and dry.  Wash and dry well, especially after exercise, and apply talcum powder to absorb moisture.  Wear cotton underclothes and avoid tight pants and pantyhose.  After swimming, put on dry clothes right away – don't stay long in a wet swimsuit.