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.
Topical antifungal agents can be used but are often ineffective. Oral terbinafine is considered to be the first-line treatment for confirmed onychomycosis; the treatment course is generally 6 weeks for fingernails and 12 weeks for toenails.9 Azoles can also be used. Surgical debridement or removal of the affected nail is also a consideration for cases that are resistant to antifungals, and laser treatments for onychomycosis appear to be a promising area for future study.10
Athlete’s foot appears as a scaly red rash on the bottoms or sides of the feet often accompanied by itching, dry or cracked skin, stinging, and odor. You can also have moist, raw skin between your toes. Though athlete’s foot is fairly easy to treat with over-the-counter anti-fungal creams or sprays, this foot fungus is quite contagious and may easily spread to your toenails.
Yeast onychomycosis: This type is caused by a yeast called Candida and not by the Trichophyton fungus named above. It is more common in fingernails and is a common cause of fungal fingernails. Patients may have associated paronychia (infection of the cuticle). Candida can cause yellow, brown, white, or thickened nails. Some people who have this infection also have yeast in their mouth or have a chronic paronychia (see above) that is also infected with yeast.
Toenail fungus is an infection that gets in through cracks in your nail or cuts in your skin. It can make your toenail change color or get thicker. It can also hurt. Because toes are often warm and damp, fungus grows well there. Different kinds of fungi and sometimes yeast affect different parts of the nail. Left untreated, an infection could spread to other toenails, skin, or even your fingernails.