Scratching infected areas may also spread the fungus to the fingers and under the fingernails. If not washed away soon enough, it can infect the fingers and fingernails, growing in the skin and in the nails (not just underneath). After scratching, it can be spread to wherever the person touches, including other parts of the body and to one's environment. Scratching also causes infected skin scales to fall off into one's environment, leading to further possible spread.
Walking barefoot in wet, dark areas frequented by many other individuals like indoor swimming pool decks, communal showers, and locker rooms result in frequent exposure to pathogenic fungi (dermatophytes) that cause athlete’s foot. Wearing occlusive footwear is thought to play a significant role in the increased frequency of tinea pedis. Exposure to moisture either from excessive sweating or from an external source is a risk factor. Wearing the same shoes and socks for an extended period may damage the skin. Patients with diabetes are predisposed to develop tinea pedis. Some believe that eczema (atopic dermatitis) can predispose one to tinea pedis. It appears that many more men have tinea pedis than women. Pedicure performed in contaminated environments can spread disease.
You may first notice a fungal toenail infection as a small white or yellow spot on the tip of your toenail, especially the big toe. As the infection progresses, the toenail can become yellow, brittle—even crumbly—and thick and uneven-looking. In the worst fungal infections, the toenail separates from the nail bed. This is called onycholysis. As fungal infections worsen, the nail beds can be tender to the touch and quite painful. Sometimes women try to pretend the pain is “normal” and ignore it altogether.
The medical name for fungal athlete's foot is tinea pedis. There are a variety of fungi that cause athlete's foot, and these can be contracted in many locations, including gyms, locker rooms, swimming pools, communal showers, nail salons, and from contaminated socks and clothing. The fungi can also be spread directly from person to person by contact. Most people acquire fungus on the feet from walking barefoot in areas where someone else with athlete's foot has recently walked. Some people are simply more prone to this condition while others seem relatively resistant to it. Another colorful name for this condition is "jungle rot," often used by members of the armed services serving in tropical climates.
If you have diabetes or a weakened immune system, treatment is especially important. After getting a fungal nail infection, people who have diabetes have an increased risk of developing sores that do not heal. Sores that do not heal can lead to a serious health problem. It’s important to see a dermatologist (or other doctor) at the first sign of a nail problem. A dermatologist can tell you whether you have a nail infection or something else.