An injury to a toenail, or even a repetitive traume to the toenail such as tight shoes or sports, can cause the nail to appear thickened and discolored.  The trauma may have damaged the nail bed, which causes the nail to uplift slightly.  Fungus is an opportunistic infection, meaning fungus is everywhere and just waits for the optimum conditions to infect a nail.  Sometimes, the trauma to the nail is the perfect condition.  By using a topical antifungal, such as Tolcylen you can make sure that any fungus that tries to infect the injured nail will be treated by that medication, thus increasing your chances to prevent a fungal infection to a damaged nail.  See our doctors at Prairie Path Foot and Ankle Clinic for more about fungal nail treatments and the proger diagnosis of fungal nails.