Current And Emerging Agents For Tinea Pedis
Recently, naftifine 2% gel (Naftin 2% gel, Merz Pharmaceuticals) garnered approval for the same dosing regimen as the 2% cream. The 2% gel was the subject of a randomized, vehicle-controlled clinical trial that enrolled patients who had interdigital tinea pedis or both interdigital and moccasin-type tinea pedis.7 The study patients used the medication for two weeks and then researchers followed them for four weeks following discontinuation of the drug. Results of the trial showed that the 2% gel was superior to vehicle at week six (four weeks post-treatment) for complete cure of people who had both interdigital and moccasin-type presentations. The study also showed naftifine 2% gel to be significantly better than vehicle in achieving mycologic cure at week six in those same patients. Overall, naftifine 2% gel was designed to provide a shorter and more convenient regimen while still maintaining the efficacy that practitioners have come to expect with the drug.
In my practice, I often see the presence of hyperkeratotic skin and tinea infection simultaneously. Hyperkeratotic tinea pedis accounts for 2 to 8 percent of tinea cases and presents as moccasin-type tinea with hyperkeratosis confined to the weightbearing areas.8 It is typically bilateral and often one only treats it with a topical antifungal. The hyperkeratosis presents a therapeutic challenge to both the patient and the physician. Often, after the tinea infection has resolved, the hyperkeratosis remains, which leads the patient to believe the infection is still present.
There is no combination product targeting both the hyperkeratosis and the tinea available at this time, but there was a pilot study using naftifine and urea on 18 patients.9 Researchers evaluated patients for eight weeks. They used the naftifine 2% cream for two weeks in the morning and applied the urea 39% cream to the affected area nightly for eight weeks. Ultimately, the evaluable patients had improvements in hyperkeratosis, the active tinea infection and pruritus. This dual therapy ultimately proved to be efficacious and cosmetically pleasing for the patients to use.
Additionally, luliconazole 1% cream (Luzu, Valeant Pharmaceuticals), a new topical imidazole, recently received approval in the U.S. for the treatment of interdigital tinea pedis. Approved in Japan since 2005, luliconazole is effective against both dermatophytes and Candida albicans, and research has shown it to be as effective as terbinafine in animal studies.10
Jarratt and colleagues reported the results of applying luliconazole 1% once daily to patients with interdigital tinea for two or four weeks in comparison to the vehicle.10 Increasing the treatment period from two to four weeks only slightly changed the mycological cure and/or clinical cure rates. This shows the potent activity of the study drug toward the dermatophyte. In addition, this study demonstrated that luliconazole 1% is not only an efficacious topical against tinea, but is also a safe and well-tolerated product. The data of the Phase III study, which supported the new FDA approval for the product, will be published within the next year.
How Effective Are Folk Remedies For Tinea Pedis?
A folk remedy in Japan involves applying green tea leaves to affected skin.11 Green tea leaves contain catechin, which seems to exhibit antioxidant properties. Green tea reportedly has activity against Candida, bacteria and fungus.
A recent study of tinea pedis patients focused on the effects of green tea polyphenol dissolved in lukewarm water foot baths for three months.11 Four bedridden patients who had plantar tinea pedis took once daily foot baths with a green tea polyphenol solution. After 12 weeks, the signs of tinea pedis had improved but researchers could not assess subjective symptoms like pruritus due to the conditions of the patients studied. Patients had no adverse symptoms but further studies will have to assess both the most efficacious concentration of green tea and patient satisfaction.