Have you ever had toenail fungus? It isn’t pretty. It can make the toenail yellow, thick, and cracked. Wearing shoes can be uncomfortable. I see this every day in my office; it is quite common, and treatment can pose a challenge. 

Toenail fungus (onychomycosis, or tinea unguium) is an infection of the toenails, and even occasionally the fingernails. It starts when fungi get beneath the nail. Fungi feed on keratin, the main structural material that makes our nails hard. Anyone can get it, although common risk factors include being over 60, suffering from athlete’s foot or diabetes, those who sweat excessively, have a nail injury, poor blood circulation, psoriasis, or a weakened immune system. Toenail fungus causes a change in nail color to white, yellow or brown. The nail is thickened and perhaps misshapen. It might separate from the nail bed, crack or break in certain areas, and form a deposit underneath.

Unfortunately, it can be quite contagious, either through direct contact, or by touching an infected surface. It doesn’t usually go beyond the nails, but it’s possible for the fungi to spread to the skin (ringworm), or to other toes, between the toes, or to the groin or scalp. 

Typically, the diagnosis is made simply and visually. Other conditions, including psoriasis, might resemble it, so a more definitive diagnosis can be made in the lab with scrapings of debris from under the nail. 

Treatment for toenail fungus is not always needed. There are, however, a few imperfect options. Oral antifungal drugs may have side effects, including rash and liver damage, so regular lab tests would be required. Topical medicines are available, including the nutritional supplement biotin (to help strengthen weak or brittle nails) and tea tree oil (which has some antifungal benefits). Trimming and thinning the nail can help. Laser treatments may lead to a temporary improvement. Note that none of these treatments offer a high cure rate; toenail fungus is notoriously tricky to treat, may take several months, and frequently comes back. The most effective but least used option is surgery. This removes the nail, so that the antifungal medicine can be applied directly to the infection. The nail eventually grows back.

You may feel tempted to cover up a discolored toenail with nail polish, but note that nail polish traps moisture. Fungi thrive in moist environments, so wearing nail polish can make a fungal infection worse. 

Given how difficult it is to treat toenail fungus, the best approach is prevention:

• Keep your feet clean and dry. Wash them with soap and water daily, and be sure to dry in between the toes. 

• Wear shower shoes around public pools, gyms, locker rooms, and showers. 

• Fungus thrives when feet are cooped up inside tight, hot shoes and socks. Put on a clean pair of socks every day. 

• Leather is a good breathable material for shoes. For socks, synthetic fiber is better than cotton and wool at pulling moisture from the feet.

• Use foot powder to dry your feet. Cornstarch can work, but medicated powder is better. Keep your toenail clippers, files and scissors clean (rubbing alcohol works well), and don’t share them. 

• Trim your toenails short and straight across. Avoid picking at the nails, or at the skin surrounding them. 

• Nail polish and fake nails can trap moisture, creating a perfect place for fungus to grow. If toenail fungus is an issue, you will want to live without them. 

• Select a nail salon that practices excellent hygiene, and consider bringing your own tools. 

• An over-the-counter anti-fungal cream can be used preventively. Watch for any change in nail color and texture. 

If you observe changes, see your doctor. Early intervention works best!