The use of the new oral antifungal agents, itraconazole, terbinafine, and fluconazole to treat onychomycosis and other dermatomycoses

Abstract

Onychomycosis refers to a fungal infection of the nail bed and secondarily the nail plate. This could be caused by dermatophytes, Candida species, and nondermatophyte molds. Tinea unguium is infection of the nail bed/plate by dermatophytes. The modified classification of onychomycosis is distal and lateral subungual onychomycosis, proximal subungual onychomycosis, superficial onychomycosis, endonyx onychomycosis, and total dystrophic onychomycosis. In general, only about 50% of all abnormal-appearing toenails can be attributed to mycologically proven onychomycosis. The other causes for abnormally-appearing nails include psoriasis, trauma, and lichen planus. The newer oral antifungal agents itraconazole, terbinafine, and fluconazole have become primary treatments of onychomycosis and other superficial fungal infections; however, griseofulvin, is widely used to treat tinea capitis and ketoconazole, is preferred by some for the treatment of tinea versicolor. Each of the new oral agents has been shown to be effective and safe in dermatomycoses. Diabetic patients are more prone to development of onychomycosis compared with normal individuals. Because of the potential for morbidity, the feet in diabetic patients need to be examined carefully, with appropriate treatment of any fungal or bacterial infection. The management strategies with onychomycosis include no therapy, use of effective topical therapies if available, mechanical or chemical debridement, or oral antifungal therapy. In some instances the most appropriate approach is a combination of two of the above-mentioned therapy modes, for example, oral therapy and mechanical debridement. The preferred dosage regimens are itraconazole (pulse), terbinafine (continuous), and fluconazole (once-weekly). Once a cure has been achieved, management includes education and counseling of the patient to reduce the chances of recurrence of disease. There is a growing body of experience in which the new oral antifungal agents have been used to treat tinea capitis and other superficial infections in children. The data suggest that itraconazole, terbinafine, and fluconazole are effective and safe in children. (Curr Probl Dermatol 2001;13:213-48)