Nail fungus (onychomycosis) is a fungal infection in either a fingernail or a toenail. The fungal infection causes discoloration and thickening of the nail.
Diagnosis can be made through physical examination and a culture of the nail. Other things can cause thickening of the nails or discoloration, including psoriasis and sometimes allergic reactions.
Treatment of nail fungus includes either a prescription topical nail polish or an oral anti-fungal medication. The oral anti-fungal medication is far more effective than any other treatments. Laser treatments for nail fungus can be effective but are expensive and have lower percentage effectiveness than the oral route.