Fungal toenail infections, often resulting in thickened, yellow, or discolored nails, affect a significant portion of the population, with prevalence increasing with age. Approximately one in ten adults has a fungal toenail infection, a figure that rises to about half of all adults by age 70. The fungi responsible, typically dermatophytes, are the same microbes that cause athlete's foot.
These fungi thrive in warm, dark, and moist environments. Consequently, everyday footwear can inadvertently create the perfect breeding ground for infection. Tight shoes, synthetic trainers worn for extended periods, and rubber-soled boots that lack ventilation can trap heat and sweat, fostering fungal growth. In contrast, open footwear like sandals, particularly those with ventilation holes such as Crocs, can help by allowing air circulation and moisture evaporation.
The choice of socks also plays a crucial role. Synthetic sports fibers and merino wool are effective at wicking moisture away from the skin, allowing it to evaporate. Cotton socks, however, absorb and retain moisture, leading to damp feet, which is conducive to fungal infections. Experts advise changing socks daily and alternating shoes to allow each pair a full 24 hours to dry out completely.
For individuals who already have a fungal toenail infection, treatment requires patience and proper application. Over-the-counter antifungal nail lacquers, such as amorolfine, are available but are often perceived as ineffective due to common mistakes in their use. A primary reason for treatment failure is insufficient duration. Toenails grow slowly, and it can take 12 to 18 months for a nail to fully grow out. Antifungal lacquers typically need to be applied once or twice weekly for at least nine to 12 months. Success is measured by the growth of new, healthy nail from the base, rather than an immediate improvement in the appearance of the infected portion.
Another common error is neglecting to file the nail before applying lacquer. Filing helps the antifungal medication penetrate the thickened nail to reach the fungus. Disposable nail files are often included with treatments for this purpose, and the nail should be filed each time before application.
Ignoring co-existing athlete's foot is also a significant mistake. If a fungal infection is present on the skin of the feet, the same fungi can reinfect the nails. Therefore, it is essential to treat both the skin and the nails concurrently, using over-the-counter creams for athlete's foot alongside nail treatments.
If at-home treatments prove ineffective despite diligent application, consulting a general practitioner is recommended. Nail clippings can be sent for laboratory analysis to identify the specific fungus, and prescription-strength oral terbinafine tablets may be prescribed. While more potent and faster-acting, these medications require monitoring due to potential liver side effects and are not suitable for everyone.
Other treatment options include laser therapy offered by some private podiatrists, though it can be costly and results vary. Some evidence suggests that tea tree oil, applied undiluted after filing, may offer benefits, particularly for early-stage infections, but it requires consistent long-term use. Apple cider vinegar, often suggested as a remedy, lacks scientific evidence to support its efficacy for toenail fungus.
To prevent the spread and worsening of infection, it is advised to dry feet thoroughly after washing, trim toenails straight across, and avoid sharing towels, nail clippers, or footwear. It is also important to treat athlete's foot promptly. While noticeable results from toenail treatment may not appear within a single summer season, consistent application of recommended strategies can lead to improvement over time, potentially by the following year.