Dermatologists treat nail problems.  Half of all nail disorders are caused by fungal infections.  Nail changes may also signal other disease such as liver and kidney disease, anemia, diabetes, or other illnesses.  Keep nails clean and dry, cut nails straight across with slight rounding in the center, wear proper fitting shoes dusted with antifungal powder.  Tight shoes may produce ingrown toenails.  Infected ingrown toenails frequently require antibiotic treatment.  If you get frequent manicures or pedicures, be aware of cleanliness and consider bringing your own instruments to avoid nail infections.  Elimination of nail fungal infections requires 3-6 months of prescription oral medication with close follow-up.