Conventional treatment typically involves thoroughly washing the feet daily or twice daily, followed by the application of a topical medication. Because the outer skin layers are damaged and susceptible to reinfection, topical treatment generally continues until all layers of the skin are replaced, about 2–6 weeks after symptoms disappear. Keeping feet dry and practicing good hygiene (as described in the above section on prevention) is crucial for killing the fungus and preventing reinfection.
For more severe cases, oral antifungal medications might be required. These include fluconazole (an antifungal agent also commonly used to treat thrush), terbinafine (a broad-spectrum antifungal) and griseofulvin (usually used for skin infections). The latter is a very old drug and carries the risk of causing damage to the liver. Terbinafine is most effective and therefore is the preferred oral treatment. A 12-week course cures 70-80% of cases by causing the fungi’s cells to leak and die. It can, however, cause gastrointestinal side effects and depression.
Over-the-counter antifungal treatments. Antifungal creams and ointments treat toenail infections while helping to keep new fungus out so new nails can grow. Some treatments must be applied every day, others are applied once a week. It’s a good idea to apply topical treatments to both the foot and nail simultaneously to prevent foot fungus from spreading to the toes. If you trim your toenails well (see above) before applying an antifungal, the medicine can reach deeper into the nailbed.
Modern treatments made surgery a last resort. “Before we had these 21st century medications, we didn’t have a good choice in how to deal with toenail fungus,” said Dr. Hinkes. “Oftentimes patients would come in, and out of frustration and lack of any real significant clinical cure with medication, they would ask for their nails to be permanently removed.”
Trichophyton rubrum is the most common dermatophyte involved in onychomycosis. Other dermatophytes that may be involved are T. interdigitale, Epidermophyton floccosum, T. violaceum, Microsporum gypseum, T. tonsurans, and T. soudanense. A common outdated name that may still be reported by medical laboratories is Trichophyton mentagrophytes for T. interdigitale. The name T. mentagrophytes is now restricted to the agent of favus skin infection of the mouse; though this fungus may be transmitted from mice and their danders to humans, it generally infects skin and not nails.
Wei, Y.-X., Xu, X.-Y., Xu, & Song, X. (2017). A review of antifungal natural products against the pathogenic fungi causing athletes' foot disease. Current Organic Chemistry, 21, 1–13. Retrieved from https://www.researchgate.net/profile/Xun_Song/publication/319128408_A_Review_of_Antifungal_Natural_Products_Against_the_Pathogenic_Fungi_Causing_Athletes'_Foot_Disease/links/59931c65458515c0ce61efa1/A-Review-of-Antifungal-Natural-Products-Against-the-Pathogenic-Fungi-Causing-Athletes-Foot-Disease.pdf
If you have diabetes or a weakened immune system, treatment is especially important. After getting a fungal nail infection, people who have diabetes have an increased risk of developing sores that do not heal. Sores that do not heal can lead to a serious health problem. It’s important to see a dermatologist (or other doctor) at the first sign of a nail problem. A dermatologist can tell you whether you have a nail infection or something else.