Toenail fungus is also known medically as onychomycosis. It is a slow-growing infection that affects the nails and the skin underneath them.
Nail fungal infections usually occur underneath the nail. This may begin at the nail’s tip, the part where it is trimmed. A toenail fungal infection is often accompanied by the following symptoms: discoloration of the nail which is usually brown, yellow, or white; nail thickening, crumbling nails, separation of the nail from the nail bed, an increase in the white debris (a protein called keratin) underneath the nail, pain coming from the nail, and a foul odor as well.