A number of different types of fungus can cause onychomycosis including dermatophytes and Fusarium. Risk factors include athlete's foot, other nail diseases, exposure to someone with the condition, peripheral vascular disease, and poor immune function. The diagnosis is generally suspected based on the appearance and confirmed by laboratory testing.
Medical treatment of onychomycosis is suggested in patients who are experiencing pain and discomfort due to the nail changes. Patients with higher risk factors for infections such as diabetes and a previous history of cellulitis (infection of the soft tissue) near the affected nails may also benefit from treatment. Poor cosmetic appearance is another reason for medical treatment.
Use soap and water to wash your feet, and dry well, including between toes. Trim your toenails -- straight across -- to keep them shorter than the end of your toe. Make sure the tools you use are clean, too. Wash clippers and files with soap and water, then wipe with rubbing alcohol. You might be tempted to cover up discolored nails with polish, but don't. Your nail bed can't "breathe," which keeps fungus from going away.