Onychomycosis is a nail infection caused by fungus. About 8% of the U.S. population is affected by nail fungus and the prevalence increases with age. The fungus causes the nail to thicken and discolor. Yellow-brown discoloration or white splotches can be common appearance. More severe infections cause the nail to change shape, curving in at the sides and distorting. The nail can become rough and crumbly. The fungus does not cause pain, but the thickness and shape can cause excess pressure and discomfort and at times lead to ingrown nails and bacterial infection. In diabetics, fungal toenails can lead to ulceration under the nail.
The most common pathogen causing onychomycosis is called a dermatophyte. Dermatophytes are fungus which live on the skin, hair and nails. “Derm” = skin and “phyte” = pathological growth. The toenails are affected more than fingernails because toenails grow more slowly, are enclosed in shoes, are frequently exposed to microtrauma and damp, moist environments. Fungus grow well in enclosed, damp environments which means that individuals with excess perspiration (hyperhidrosis) of their feet and athletes who must be in athletic shoes for long periods of time are more susceptible to developing foot and toenail fungus. Gyms, showers and public pools are common areas for fungus.
A combination of factors contribute to the development of a fungal infection in the nails. Simply coming into contact with fungus will not cause an infection. When the skin is moist, it causes loosening of the bonds and increases the chances of infection. Prolonged exposure to the fungus will also increase the chances of infection. Individuals who are in closed shoes which lack breathability for long periods and perspire due to exercise or warm weather are more likely to develop a foot or toenail fungus. Fungus are more likely to invade through small breaks in the skin around the nail. Runners who experience repetitive microtrauma at the toes from shoe pressure, or individuals wearing tight, narrow shoes or boots are at higher risk of infection. Dry or cracked skin around the nail or the existence of an ingrown nail, even if it’s mild, will increase the chances of a fungal infection. Once the nail is infected it becomes extremely difficult to treat.
There are many treatments for nail fungus and they range from natural therapies to prescription oral medications. Most topical treatments have not proven to be very effective in the past and many of the oral medications are too costly or associated with side effects. A new study in the Journal of Foot and Ankle surgery evaluated ciclopirox and debridements in patients with onychomycosis and found the combination to be effective (JFAS Volume 48, Issue 3, Pages 294-308 May 2009).
The researchers evaluated 55 patients with 289 toenails with onychomycosis. The patients were randomly divided into two treatment groups, debridement only or debridement with daily ciclopirox (Penlac® ) application. The follow-up average about 10.5 months and results showed that the group treated with both ciclopirox and debridement had a 76% mycological cure rate, which was a statistically significant improvement over those in the debridement only group. Patients with hyperhidrosis (sweaty feet), lunula involvement, positive yeast culture or who smoked cigarettes had a lower rate of mycological cure.
This study was funded by Dermik Laboratories, manufacturers of Penlac® Nail Lacquer.