Toenail Fungus: Signs, Prevention and Treatment Options

Toenail fungus is a common infection that makes nails thick, discolored and brittle. Mild, early cases may respond to over-the-counter care, while stubborn cases often need prescription treatment. Either way, expect it to take months, because a clear nail has to grow out slowly. Good foot habits can help lower your risk of getting it, or getting it again.

This guide covers the signs, who is most at risk, your treatment options and when to see a doctor.

What is toenail fungus?

Toenail fungus is also called onychomycosis. The American Podiatric Medical Association describes it as an infection underneath the surface of the nail caused by fungi (APMA).

It can affect fingernails, but it is more common in toenails (Mayo Clinic). According to Cleveland Clinic, a group of fungi called dermatophytes causes about 90% of toenail fungal infections (Cleveland Clinic).

Common signs of toenail fungus

The NHS notes that it often starts at the edge of the nail and may then spread across the whole nail (NHS). Signs can include:

• White, yellow or brown discoloration
• A chalky or cloudy look
• Thickening that makes the nail hard to trim
• Brittle, crumbly or ragged edges
• A misshapen nail, or one that lifts away from the nail bed
• Debris building up under the nail
• A bad smell

Toenail fungus usually isn't painful, especially early on (Cleveland Clinic). Other conditions, such as nail psoriasis or an injury, can look similar. That is one reason a proper diagnosis matters (AAD).

How common is it, and who is at higher risk?

Cleveland Clinic says experts estimate toenail fungus affects about 1 in 10 people overall. For people older than 70, the estimate rises to about 1 in 2 (Cleveland Clinic).

Your risk may be higher if you:

• Are an older adult
• Have had athlete's foot
• Sweat heavily or wear shoes that keep feet warm and damp
• Walk barefoot in pools, gyms or shared showers
• Have had a nail or skin injury
• Have psoriasis, diabetes, poor circulation or a weakened immune system

These risk factors come from Mayo Clinic and Cleveland Clinic (Mayo Clinic; Cleveland Clinic).

Why toenail fungus is slow to clear

Toenails grow slowly. Even after the fungus is under control, the damaged part of the nail stays until it grows out.

The American Academy of Dermatology (AAD) says that with the oral drug terbinafine, the infection clears in 6 to 12 weeks. However, the nail can take a year or longer to grow out. A fully removed toenail can take 12 to 18 months to regrow (AAD).

The NHS says pharmacy nail treatments are used for 6 to 12 months. It may take several months before you see any improvement (NHS). The infection can also come back after it clears, so patience and prevention both matter.

Treatment options: over-the-counter vs. prescription

Over-the-counter care

OTC antifungal nail liquids are usually brushed onto the nail. APMA notes that home care, such as daily cleansing and OTC antifungal liquids, may temporarily suppress mild infections. It also says even the best options may not prevent the infection from coming back (APMA).

A few points to keep in mind:

• Antifungal creams made for athlete's foot treat skin, not nails (AAD).
• The AAD says small studies suggest tea tree oil may help, but its effectiveness is unknown and larger studies are needed.
• Topical products tend to make the most sense for mild, early cases.

If you want to try a topical option, ZetaClear is a brush-on nail solution. Its active ingredient is undecylenic acid, an OTC antifungal. It also contains tea tree, almond, lavender, citronella and clove bud oils, plus vitamin E. Like any topical product, results vary, and it is best suited to mild cases. Use it consistently and allow months for new nail to grow in.

Prescription treatment

For moderate to severe cases, a doctor may suggest prescription options (AAD; Cleveland Clinic):

• Oral antifungals, such as terbinafine or itraconazole. These are often taken for about 12 weeks for toenails. They may need liver blood tests and can interact with other medicines.
• Prescription topicals, such as efinaconazole, tavaborole or ciclopirox nail lacquer. Some are applied daily for about 48 weeks.
• In-office procedures, such as thinning the nail or removing part or all of it.

APMA says oral FDA-approved antifungals may be the most effective option (APMA). The AAD notes that the FDA has not approved lasers to treat the infection itself (AAD).

How to help prevent toenail fungus

These everyday habits come from APMA, Mayo Clinic, Cleveland Clinic and the NHS:

1. Keep feet clean and dry. Wash with soap and water, then dry well, including between the toes.
2. Wear shower shoes in shared spaces. Use flip-flops at pools, gyms and locker rooms.
3. Choose breathable footwear. Pick well-fitting shoes that don't squeeze your toes. Replace or disinfect old shoes.
4. Change socks often. Moisture-wicking socks can help if your feet sweat.
5. Care for nail tools. Disinfect clippers after each use, and don't share clippers, towels or shoes.
6. Trim nails straight across. Keep them short and smooth the edges.
7. Treat athlete's foot promptly. It can spread to the nails.
8. Choose salons carefully. Use one that sterilizes its tools, and skip polish on a nail you think is infected.

When to see a doctor

See a doctor or podiatrist if any of these apply (Mayo Clinic; Cleveland Clinic; NHS):

• You have diabetes, poor circulation or a weakened immune system
• You notice pain, redness, swelling, bleeding or pus around the nail
• The infection is spreading to other nails
• Self-care hasn't helped and the nail keeps changing
• You have trouble walking

Redness, swelling and pus can be signs of a bacterial infection. Cleveland Clinic notes that untreated toenail fungus can rarely lead to cellulitis, a skin infection (Cleveland Clinic). APMA adds that earlier treatment improves the chance the nail will clear.

Frequently asked questions

Can toenail fungus go away on its own?

It usually doesn't clear without treatment and can last for years. Cleveland Clinic notes that a mild case that doesn't bother you may not need treatment. A doctor can help you decide.

How long does it take to treat toenail fungus?

Usually many months. The NHS says pharmacy treatments are used for 6 to 12 months. Even after the infection clears, the AAD says the nail can take a year or longer to grow out.

Do over-the-counter nail treatments work?

They may help with mild, early infections, but results vary. APMA says OTC liquids may temporarily suppress mild infections. Moderate to severe cases often need prescription treatment.

Is toenail fungus contagious?

It can spread to other nails and to skin. Sharing towels, shoes or nail clippers may also spread it. Wearing shower shoes in shared spaces can help lower your risk.

Can I wear nail polish over toenail fungus?

It's best to avoid it. APMA and Mayo Clinic both suggest skipping polish on a nail you think is infected.

Should people with diabetes treat toenail fungus at home?

They should see a doctor first. Mayo Clinic and the NHS both advise this, because foot problems can be more serious with diabetes.

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Sources

• American Academy of Dermatology: Nail fungus: Diagnosis and treatment
• Mayo Clinic: Nail fungus, symptoms and causes
• Cleveland Clinic: Toenail Fungus (Onychomycosis/Tinea Unguium)
• American Podiatric Medical Association: Toenail Fungus
• NHS: Fungal nail infection

This article is for general information and is not medical advice. Results from topical products vary, and people with diabetes or circulation problems should see a doctor before treating their feet at home.