Fungal infections, such as Athlete’s Foot, thrive in the warm, dark, and humid environment inside footwear. The fungi responsible, known as dermatophytes, leave behind microscopic spores that can survive for extended periods on the inner surfaces of your shoes and socks. This persistent contamination creates a reservoir that can lead to reinfection, even after a skin infection has been successfully treated. Sanitizing footwear is necessary to break this cycle of recurrence and eliminate the fungal spores.
Sanitizing Washable Shoes
Shoes made of durable materials like canvas, most athletic sneakers, and some synthetics can be cleaned using immersion methods. Before washing, remove both the insoles and laces, as these items harbor fungal spores. Insoles should be cleaned separately using a disinfectant solution, while laces can be washed with the shoes.
For machine washing, select a hot water cycle, ideally 140°F (60°C) or higher; this thermal exposure kills fungal spores on textiles. Enhance the sanitizing power by adding laundry detergent along with a laundry sanitizer, borax, or half a cup of white vinegar to the wash. If the shoe material is white and bleach-safe, a diluted solution of chlorine bleach can also be added.
Immediate and thorough drying after washing is important, since lingering moisture promotes the growth of new fungi and mold. Do not place the shoes in a machine dryer, as the heat can melt adhesives and damage the structure. Instead, allow them to air dry completely in a well-ventilated area, or use a dedicated shoe dryer that circulates air.
Disinfecting Materials That Cannot Be Washed
Footwear made of delicate materials like leather, suede, or certain dress shoes cannot be immersed in water or exposed to high heat without risking damage. For these items, non-immersion methods must be used to target the fungi inside the shoe. Commercial antifungal sprays or powders designed for footwear are effective and contain active ingredients like miconazole or tolnaftate, which kill dermatophytes.
To apply, spray or sprinkle the product liberally inside the shoe, ensuring it reaches the toe box and all interior fabric surfaces. For a natural alternative, a solution of white vinegar diluted with water can be sprayed inside, or baking soda can be applied to absorb moisture and odor. Always test any liquid application on a small, hidden area first to check for discoloration or staining.
Specialized tools like ultraviolet-C (UVC) shoe sanitizers are an effective, chemical-free option for non-washable shoes. UVC light works by damaging the DNA of microorganisms, including fungal spores, rendering them inactive. These devices are inserted into the shoe and run a short cycle, reducing the fungal burden in contaminated footwear.
Preventing Fungal Recurrence in Footwear
Sanitization is only the first step; maintaining a dry environment inside your shoes is necessary for prevention. Fungi thrive in moisture, so rotate your footwear, avoiding wearing the same pair on consecutive days. This provides at least 24 hours for each shoe to dry out completely between uses.
Wearing moisture-wicking socks made from technical synthetic fabrics or wool, rather than cotton, helps pull sweat away from the skin and reduces the moisture trapped inside your shoe. When storing shoes, avoid damp closets or sealed containers and choose a cool, well-ventilated space. If a pair of shoes is heavily contaminated and cannot be thoroughly cleaned, it may be necessary to discard them to prevent spreading the infection to new footwear.
To accelerate drying, stuff shoes with crumpled newspaper or use an electric shoe dryer, which gently circulates air. Applying an antifungal powder or spray inside the shoes weekly, even after the initial infection has cleared, creates a hostile environment for any new spores. Consistent maintenance and moisture control are the best defenses against recurrence.