Onychomycosis.(WOMEN'S HEALTH ADVISER)

Onychomycosis--fungal infection of the toenails or fingernails--is a common problem, affecting up to 25% of the population. The most common infective organisms--Trichophyton mentagrophytes and Trichophyton rubrum--are dermatophytes commonly present in soil and on human skin. These microorganisms usually get a toehold when a nail is damaged in some way. The trauma can be caused by something as inconspicuous as a tight-fitting shoe that puts constant pressure on a nail or the end of a toe. Of all fungal nail infections, about 80% are of the big toenail and 20% are of the fingernails.

Diagnosis

The daily environment for most feet--the dark, moist warmth of socks or stockings in shoes--is the perfect habitat for fungal growth. Women who make frequent visits to the gym or pool may be at increased risk for these infections, as their feet are even more exposed to moisture and warmth. Pregnant women, whose feet change shape because of edema or ligamentous laxity, should be counseled to change shoe sizes or types as these changes occur. This may help prevent nail trauma that can predispose them to onychomycosis.

Women with chronic diseases such as diabetes, circulatory problems, or immune deficiency conditions are especially prone to fungal nail infections. Other contributory factors may be a history of athlete's foot and excessive perspiration. The first symptom is a change in nail color, usually yellow streaks in the nail bed and beneath the nail. Later, the nail may become brittle or crumbly, lose its luster, thicken, or become dystrophic. Debris may be present under the nail, which eventually may become loose or even detach. The toes may be malodorous and the skin around the nail may become inflamed.

Management

A culture is usually recommended to identify the infective organism. Yeasts and molds can also be causative agents.

Because the toenails grow so slowly, it will take months--even up to 1 year--to see complete clearance of symptoms with any drug therapy Sometimes, even with mycologic cure, the nail will remain deformed. If the entire plate has been affected, the fungus has probably invaded the nail bed; this may have damaged the nail matrix, resulting in permanently dystrophic nails.