Itraconazole and Terbinafine Treatment of Some Nondermatophyte Molds Causing Onychomycosis of the Toes and a Review of the Literature

Background: Onychomycosis may be caused by dermatophytes (which form the majority of organisms), Candida species, and nondermatophyte molds. Objective: To evaluate the efficacy and safety of itraconazole and terbinafine in the treatment of some nondermatophyte molds that cause toe onychomycosis and to review the literature on the treatment of nondermatophyte mold toe onychomycosis using the oral antifungal agents. Patients and Methods: Patients with nondermatophyte mold toe onychomycosis were treated in an open, prospective manner with either itraconazole (pulse) or terbinafine therapy. In each instance, light microscopic examination was consistent with the diagnosis of a nondermatophyte mold. For each patient, mycological evaluation of the target nail resulted in 3 or more successive cultures yielding growth of the mold alone. Results: All 15 patients had onychomycosis of the toes which was of the distal and lateral type. The patients were treated with itraconazole given as the standard 3 pulses with additional pulses administered depending upon the response exhibited by the toe onychomycosis in the patient. Similarly, terbinafine was given for 12 weeks with additional therapy administered as dictated by the response. Efficacy parameters were mycological cure (MC) and clinical cure (CC). Mycological cure was negative light microscopic examination (KOH) and culture. Clinical cure was the appearance of a completely normal-looking nail. At month 12 from the start of treatment, the response was as follows: Scopulariopsis brevicaulis: itraconazole (MC 4/4, CC 2/4) and terbinafine (MC 0/1, CC 0/1), Fusarium species: itraconazole (MC 1/1, CC 1/1) and terbinafine (MC 0/1, CC 0/1), Aspergillus species: itraconazole (MC 5/6, CC 3/6), Alternaría alternata: itraconazole (MC 0/1, CC 0/1), and Onychocola canadensis: itraconazole (MC 1/1, CC 0/1). There were no significant clinical or laboratory adverse effects. Conclusions: In the present series itraconazole demonstrated efficacy against onychomycosis of the toenails caused by 5. brevicaulis and Aspergillus species. A review of the literature confirms our experience with itraconazole and further suggests that terbinafine may also demonstrate efficacy against cases of S. brevicaulis and Aspergillus toe onychomycosis. Additionally, reports in the literature suggest that pedal onychomycosis caused by Fusarium species may also show response to itraconazole and terbinafine. For the other species, there are fewer data, making it difficult to draw conclusions.