Toenail fungus is an organism called onychomycosis or tinea unguium. Small amounts of this fungus and other organisms live on your body every day, but when the fungus begins to overgrow, you develop an infection.
Fungal toenail infections tend to develop slowly, but you should get treatment as soon as you notice symptoms. The infection will usually get more challenging to treat as it progresses, and it could spread to other toenails or your fingernails.
The most common places that you might pick up a fungal toenail infection is at a public pool or a shared shower area. Fungal infections thrive in a warm and moist environment. If you have a nick or a break in your toenail and you come into contact with the fungus, it will enter your toenail and begin to multiply. You should always wear shower shoes or flip-flops instead of walking around barefoot in these environments. If you participate in a sport or exercise regularly, make sure to change out of your sweaty socks and sneakers when you’re finished, so you can keep your toes clean and dry.