Onychomycosis is a fungal infection of the toenails or fingernails that may involve any component of the nail unit, including the matrix, bed, or plate. Onychomycosis can cause pain, discomfort, and disfigurement and may produce serious physical and occupational limitations, as well as reducing quality of life. See the image below.
Topical antifungals
The use of topical agents should be limited to cases involving less than half of the distal nail plate or for patients unable to tolerate systemic treatment. Agents available in the United States include ciclopirox olamine 8% and efinaconazole 10% nail solutions. Amorolfine and bifonazole/urea are available outside of the United States.
Topical treatments alone are generally unable to cure onychomycosis because of insufficient nail plate penetration. Ciclopirox and amorolfine solutions have been reported to penetrate through all nail layers but have low efficacy when used as monotherapy. [27] They may be useful as adjunctive therapy in combination with oral therapy or as prophylaxis to prevent recurrence in patients cured with systemic agents. Daily application and a long duration of treatment (48 wk) are required for efinaconazole and ciclopirox.
Efinaconazole is indicated for toenail onychomycosis. Its approval was based on 2 phase III multicenter, randomized trials (N = 1,655). Complete cure was seen in 17.8% and 15.2% of patients receiving the drug, versus 3.3% and 5.5% of subjects receiving the vehicle. Mycologic cure rates were significantly greater with efinaconazole (53.4-55.2%) compared with the drug vehicle (P < .001). [28, 29, 30]
Tavaborole, a topical oxaborole antifungal (boron-containing compound) is indicated for onychomycosis of the toenails due to Trichophyton rubrum or Trichophyton mentagrophytes. Its approval was based on 2 multicenter, double-blind, randomized trials involving 1194 subjects. After 48 weeks of treatment, complete cure was found in 6.5% and 9.1% in patients receiving tavaborole compared with 0.5% and 1.5%, respectively, of patients applying the vehicle alone. [31] Mycological cure was obtained in 31.1% and 35.9% for active treatment versus 7.2% and 12.2% for the vehicle.
Oral therapy
The newer generation of oral antifungal agents (itraconazole and terbinafine) has replaced older therapies in the treatment of onychomycosis. [32, 33, 34] They offer shorter treatment regimens, higher cure rates, and fewer adverse effects. Fluconazole and the new triazole posaconazole [3] (both not approved by the US Food and Drug Administration [FDA] for treatment of onychomycosis) offer an alternative to itraconazole and terbinafine. The efficacy of the newer antifungal agents lies in their ability to penetrate the nail plate within days of starting therapy. Evidence shows better efficacy with terbinafine than with other oral agents (see Prognosis).
