(HealthDay News) -- Toenails are susceptible to a fungal infection called onychomycosis, which should receive medical treatment.

Here are some common symptoms of a toenail fungal infection, courtesy of the American College of Foot and Ankle Orthopedics and Medicine:

• Yellow or discolored toenails.
• Toenails that are very thick and difficult to cut.
• Toenails that have separated from the nail bed.
• Crumbling toenails.