Does toenail fungus have to be treated? what happens if left untreated

Not necessarily: Toenail fungus or onychomycosis is usually caused by a fungal infection similar to athlete's foot. This is usually not a harmful condition, but is often unsightly and may make the nail thick, brittle and hard to cut. This condition can on occasion cause pain in shoes from pressure on the nail bed. Treatment may include: oral antifugals, topical meds, laser treatment, permanent nail removal.

A cosmetic problem: Toenail fungus is a fairly common condition, more so as a person ages. It rarely leads to any significant medical complications. For that reason insurance companies do not cover the cost of treatment. There are 2 medications that work about 50% of the time. Laser treatments have had similar success. If left untreated the nail thickens and discolors.