Nail fungus, or “onychomycosis” affects about 10% of the U.S. population.  Four types of onychomycosis are recognized based on the site and pattern of fungal invasion. Dermatophyte fungi are the predominant pathogens, but yeasts (especially Candida albicans) and nondermatophyte molds may also be implicated. Dermatophytes are specialized organisms that live off keratin which is the main component of nails and skin.

Affected nails become yellow or discolored. As the infection advances, the nail can become thick, brittle, and separate from the nail bed. It can cause pain when wearing shoes or walking.

Oral antimycotic (fluconazole, itraconazole, and terbinafine) can be taken for months in an effort to resolve toenail fungus, but have potential side effects as well as high cost, and are often not covered by insurance which may deem this a ‘cosmetic’ condition. The possibility exists of liver injury during therapy with the newer antifungal agents. Liver function tests at baseline and periodically during therapy should be performed for patients receiving continuous therapy with terbinafine, fluconazole, or itraconazole. Patients receiving terbinafine are also advised to undergo baseline and periodic complete blood counts as well. Pulse therapy with itraconazole does not require laboratory monitoring. The recommendations for intermittent therapy with fluconazole are unknown. In all cases, patients should be educated so that they can recognize and report signs of drug-related adverse reactions, including jaundice, upper abdominal tenderness, malaise, dark urine, pale stools, fatigue, nausea, and vomiting.