Anyone who enjoys wearing open-toed sandals in the summer knows how good it feels to have healthy-looking toenails. But good looks aren’t the only reason to keep your toenails in top shape. Fungal infections of the toenails — also known as onychomycosis — don't go away on their own, and if left untreated, the fungus will spread and can eventually destroy the nail.

If you have comprised blood flow, there’s even more reason to safeguard your toenails, since you’ll have trouble healing, says Ami Sheth, a doctor of podiatric medicine in Los Gatos, California, and a spokesperson for the American Podiatric Medical Association. “And once you have a wound, you can get fungal skin infections, which can lead to a subsequent bacterial infection if the skin breaks down,” notes Dr. Sheth.

However, because toenail fungal infections are typically painless, people are often unaware that they have a problem unless they are inspecting their feet regularly.

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Preventing Toenail Fungus From Spreading

While you can't avoid contact with the microscopic organisms that cause toenail fungus — it’s present anywhere that is warm, dark, or moist — keeping your feet clean and dry and clipping your nails properly can help prevent an infection.

For fungus to grow, “there needs to be some type of trauma to the nail where the nail-skin junction, or natural barrier, is disrupted,” says Sheth. “For example, from a pedicure, ill-fitting shoes, or the repetitive trauma of running or hiking that causes the nail to lift or get pressed on from shoes or boots.”

Still, some people are more vulnerable than others, she adds. “Some people have it only on one toe or one foot, and some have lived with a partner who has it but they never get it," Sheth says. "And for some you see it in their entire family. It's not as straightforward as it seems, and it's an annoying problem.”

If you do get a toenail fungus infection, these measures can help stop it from spreading:

Wash your feet and dry them thoroughly before putting on your socks and shoes.
Clip your toenails straight across so the nail doesn't extend past the tip of the toe — this helps protect the delicate tissue beneath the nail.
Wear properly fitting shoes that allow your feet to breathe. If your feet become damp, change your socks to a dry pair as soon as possible.
Spray your shoes with an over-the-counter antifungal product. ”Your shoe is a great environment for fungus to thrive,” notes Sheth.
Wear shower shoes in public places where others typically walk barefoot, such as in locker rooms and around pools.
Thoroughly clean your nail clippers and other pedicure tools between use.

Getting rid of established toenail fungus can be difficult. Successfully eliminating it depends on careful adherence to a treatment plan.

"What happens over time is that the fungus breeds in the nail tissue and goes from being just a little bit on the nail, to a really discolored and thickened nail, to a nail that is totally embedded with fungus," explains Marlene Reid, a doctor of podiatric medicine in Naperville, Illinois, and a spokesperson for the American Podiatric Medical Association.

Treating Toenail Fungus Medically

How a toenail fungal infection is treated may depend on its severity.

In white superficial onychomycosis, for example, the white patches of fungus that form on the nails can sometimes simply be filed off and an over-the-counter antifungal topical medication can be applied to the nail to kill the fungus.

For infections affecting deeper layers of the nail, over-the-counter topical medications often don't penetrate the nail deeply enough to kill all of the fungus and prevent the infection from recurring. Repeated applications of the medication or a prescription-strength drug may be necessary.

The symptoms of more severe infections include thickened, discolored toenails that may eventually become painful. In these situations, you should see a podiatrist who can devise a treatment plan that may include these actions:

Debridement The thickened portions of the nail can be debrided, or removed, to reduce pain and allow a topical treatment to penetrate more effectively.

Topical Medication Medications that are applied like nail polish or hand cream are sometimes used to treat nail infections. However, topical medication often fails because it doesn't move deeply enough into the nail to reach the fungus or users forget to apply it daily for almost a year, as is required.

Oral Medication Oral medications used to treat toenail fungus include terbinafine (Lamisil) and itraconazole (Sporanox, Onmel). Both medications require at least a three-month course of treatment for toenails; if used consistently, they have a good success rate. Because both drugs can affect the liver, however, blood tests of liver function are recommended before treatment is started and every four to six weeks during treatment. A third medication, fluconazole (Diflucan), is sometimes used on an off-label basis for toenail fungus caused by yeast.

Nail Removal, Home Remedies, and Laser Treatment

In the most serious instances of toenail fungus infection, the toenail may be removed surgically or dissolved with acid. This can be done to just a portion of the nail in the hope that the remaining nail will grow back healthy. In cases where the entire toenail has to be removed, artificial nails and products using light-cured resins to form a temporary covering can be used to protect the underlying tissue until the nail grows back.

If you prefer to go the home-remedy route, such as applying tea tree oil or Vicks VapoRub to your nails, keep in mind that the effectiveness of these products for treating toenail fungus hasn't been well studied, and they are not recommended by podiatrists.

Finally, the Food and Drug Administration has approved several laser devices for “temporary increase in clear nails in patients with onychomycosis.” But while laser treatments are vigorously marketed, clinical trials of lasers have reported mixed results, and the treatments may not be covered by health insurance. If you wish to try laser treatment of toenail fungus, speak to your doctor about what to expect from the treatment, and call your insurance carrier to find out whether the treatment will be covered.

Additional reporting by Susan Jara.