Fungal infections can affect any part of the body. Fungi are normally present in and on the body alongside various bacteria. When a fungus begins to overgrow, you can get an infection.
Onychomycosis, also called tinea unguium, is a fungal infection that affects either the fingernails or toenails. Fungal infections normally develop over time, so any immediate difference in the way your nail looks or feels may be too subtle to notice at first.
Fungi thrive in warm, moist environments, so this type of environment can cause them to naturally overpopulate. The same fungi that cause jock itch, athlete’s foot, and ringworm can cause nail infections.
Fungi that are already present in or on your body can cause nail infections. If you have come in contact with someone else who has a fungal infection, it may have spread to you. According to the American Academy of Dermatology (AAD), fungal infections affect toenails more commonly than fingernails because your toes are usually confined to your shoes, where they’re in a warm, moist environment.
If you get a manicure or pedicure at a nail salon, be sure to ask how the staff disinfects their tools and how often they do it. Tools, such as emery boards and nail clippers, can spread fungal infections from person-to-person if they’re not sanitized.