Current And Emerging Agents For Tinea Pedis
There is no shortage of over-the-counter and prescription remedies for tinea pedis. With this in mind, this author takes a look at the research and clinical experience regarding several emerging treatment agents, including new topicals and medical socks.
One of the most common infections in the United States, tinea pedis is consistently the result of dermatophytes. These skin, hair and nail-preferring fungi consist of Trichophyton sp., Microsporum sp. and Epidermophyton sp., of which the top pedal pathogen is Trichophyton rubrum. Dermatophytes are highly contagious and may transfer via soil, animals, humans and fomites.
Wearing shoes, sneakers or boots leads to creating a warm and moist environment, which is an optimal place for fungus to thrive. Traditionally, tinea pedis occurs in the pedal interdigital areas, where prolonged moisture will cause macerated tissue to occur. However, it also presents on the plantar surface of the foot as dry, scaly and itchy skin known as the moccasin type. Populations at risk to develop tinea pedis include: those who use communal facilities (pools, dorm showers, gyms); those who wear rubber or non-breathable material shoes at work; and those who have diabetes or are obese, immunocompromised, vascularly compromised and unable to perform regular foot hygiene.
Treatment options have consisted of both prescription and over-the-counter topical medications, such as naftifine (Naftin 1% or 2%, Merz Pharmaceuticals), econazole (Spectazole, Fougera Pharmaceuticals) and ciclopirox (Loprox, Medicis). Oral medications consist of off-label uses for terbinafine (Lamisil, Novartis) and itraconazole (Sporanox, Janssen Pharmaceuticals) and on-label use for griseofulvin ultramicrosize (Grifulvin V, OrthoNeutrogena).
Even after educating the patient on the basics of pedal hygiene (drying between toes, changing socks and shoes daily, disinfecting family showering areas, and wearing shower shoes in communal areas), the physician will typically continue to manage the patient for a persistent and irritating plantar infection weeks to months after treating the initial infection.
Prior to seeking medical attention, the patient will often self-treat with over-the-counter topical preparations that consist of medicated foot powders, sprays and creams, such as Castellani’s paint, gentian violet, undecylenic acid, miconazole, clotrimazole (Canesten, Bayer), tolnaftate (Tinactin, Schering-Plough), butenafine (Lotrimin, Merck) and terbinafine. After a frustrating trial with many of these products, patients will finally seek professional advice. As medical professionals, we often prescribe the same product time and time again, and may be unaware of the emerging treatments available for tinea pedis.
A Closer Look At Emerging Treatments
A member of the allylamine class, naftifine exhibits fungicidal, anti-inflammatory and antibacterial properties.1-4 In vitro, naftifine exhibits fungicidal activity against the dermatophytes and many Candida species. It stops fungal growth by inhibiting squalene epoxidase in the ergosterol synthesis pathway, which ultimately increases cell membrane fragility and permeability.
The mycological and clinical cure rates for naftifine in the treatment of tinea are superior or equivalent to those of terbinafine, econazole and tolnaftate.5 In 2011, Parish and colleagues showed that once-a-day use of naftifine 2% cream for two weeks in the management of interdigital tinea pedis had efficacy responses equivalent to naftifine 1% cream, which patients traditionally used for four weeks for the same infection.6