The cause of nail fungal infections is usually dermatophyte fungus, but mold and yeast may also cause fungal infections, according to Mayo Clinic. These fungi often live in moist, warm environments, can get into the nail by entering small cuts in the skin, or enter the nail bed through space under the nail.
Symptoms of nail fungus include thick, crumbly or brittle nails, dark nails or nails that have unusual shapes, explains Mayo Clinic. If an infection occurs in the toenail, pain in the toes, a foul odor or separation of the nail from the nail bed may also occur. Many people find relief by using over-the-counter fungal treatments, but if these do not work, a patient must see a doctor.
To treat nail fungus, a doctor may prescribe oral antifungal drugs, medicated nail polish and nail cream, claims Mayo Clinic. The polish and cream may work better if the nails are thin, so a doctor may also suggest thinning the nails with urea, which is available at drug stores. It is also possible to thin the nails by filing them. If medications do not work, a doctor may then suggest the removal of the nail. Another treatment for treating nail fungus is the application of lasers or special lights.