Current issues in onychomycosis

To review the epidemiology, mycology, clinical features and diagnosis, current pharmacotherapy, and pharmacoeconomics of onychomycosis.

We conducted a MEDLINE search from 1966 to May 1997. References from these articles, manufacturers of the discussed antimycotics, and relevant abstracts from recent dermatology conferences were used to collect pertinent data.

Data were obtained from published controlled studies and case reports. In the pharmacotherapy section, the most weight was placed on fully reported, randomized, controlled comparative trials, but abstracts and case series were included when well-controlled studies were unavailable.

Onychomycosis is a common nail disorder that has a substantial impact on patients' quality of life. It is most commonly caused by dermatophytes, but yeasts and molds can also be involved. Diagnosis is made through clinical presentation, potassium hydroxide preparations, and culture of tissue/nail samples. Griseofulvin was the drug of choice for many years, but its low cure rates and the development of newer, more effective drugs made it fall out of favor. Current therapeutic alternatives include fluconazole, itraconazole, and terbinafine. Data on the use of fluconazole are limited to case series and reports. Continuous dosing of itraconazole and terbinafine are well-proven therapies. New data are becoming available on the use of pulse itraconazole dosing, which has recently been approved by the Food and Drug Administration for fingernail infections. These drugs are well tolerated, but attention to drug interactions is necessary with the azoles.

Currently, continuous terbinafine appears to be the most cost-effective drug for dermatophyte onychomycosis.