Toenail fungus, or onychomycosis, is common, affecting three to five percent of Americans. It can start with simple athlete’s foot, a fungal infection that, if untreated, can lead to infection deep into the nail matrix, from which the nail grows.
The microorganism that causes toenail fungus is a dermatophyte, which lives on keratin, the protein that nails are made of, and thrives in the dark, moist, warm environment of sweaty feet. (Fingernails are much less susceptible to fungal attack because they are usually cleaner and dryer.)
As toenail fungi grow, the nails become thicker and may smell foul. The thickened nails can then press into the nail bed, causing pain, especially in tight shoes.
Topical prescription solutions such as Loprox, Loceryl, Keralac and Penlac may help, said Dr. Peter Paicos, Jr., immediate past president of the Massachusetts Podiatric Medical Society and associate medical director of the wound healing center at Winchester Hospital. There are also some non-prescription topical solutions available, including Mycocide NS.
If topical treatments don’t work, you can try oral medications such as Lamisil or Sporanox, which are usually taken daily for 12 weeks. But the oral medications can, in rare cases, cause liver damage. For that reason, you should get a liver function test before starting these medications and then during the course of treatment as well, said Dr. Joseph Caporusso, a McAllen, TX podiatrist and trustee of the American Podiatric Medical Association.
In really stubborn cases, the permanent solution is to surgically remove the infected nail and nail root. Cosmetically, the result is “mostly acceptable,” said Caporusso, and women often paint the area with nail polish as they would a normal nail.
To prevent toenail fungus in the first place, wear comfortable shoes that allow your feet some breathing room, wear sandals in public locker rooms, wash your feet every day, wear clean socks or stockings every day, according to the Harvard Medical School website.