Toenail fungus: treatments that work, and why it takes a year

Fungal toenails are one of the most common nail problems, and one of the most frustrating, because treatment is slow and the infection can come back. Knowing what works, and what to expect, makes the process a lot less discouraging.

Is it really fungus?

Not every thick, yellow nail is fungal. Repeated minor injury (common in runners and people whose toes hit the end of their shoes), psoriasis and other conditions can make nails look just the same.^[2] Because treatment is long and oral medication can have side effects, the diagnosis should be confirmed with a nail sample before starting.^[1] We take the sample in the office; it’s quick and painless.

The options

Oral antifungal medication is the most effective. In a Cochrane review of 48 studies, high-quality evidence showed terbinafine and the azole antifungals were far more effective than placebo at clearing toenail infections.^[3] Terbinafine is usually taken daily for about three months. It’s generally well tolerated; the most commonly reported side effects are stomach upset and headache, and we check your health and other medications before prescribing it.^[3]

Topical treatments (lacquers and solutions) are easier to use and avoid the side effects of pills, but they must be applied daily for around a year and clear the infection less often. In a Cochrane review, ciclopirox lacquer was more effective than an inactive lacquer, but complete clearance was uncommon overall.^[4] Over-the-counter topical products have poor long-term results.^[5]

Debridement: thinning a thick nail in the office relieves pressure and pain in shoes, and helps topical treatment reach the infection.

Treating athlete’s foot at the same time, since infected skin is a common source of re-infection.^[2] See athlete’s foot.

What to expect

• The infection stops spreading first; the damaged part of the nail doesn’t heal, it has to grow out.
• New, clear nail appears at the base and slowly pushes the old nail forward.
• A big toenail grows out completely in about 12 to 18 months; smaller nails take less time.
• Infections can return, so prevention continues after treatment.

Preventing a recurrence

• Keep feet dry, change socks daily, and rotate shoes.
• Wear sandals in locker rooms and communal showers.
• Treat athlete’s foot promptly.
• Keep nails trimmed straight across and not too short.
• Consider disinfecting or replacing old shoes.

Common questions

What about laser and light treatments?

Newer approaches such as light-based (photodynamic) and plasma therapies have been explored for fungal nails, but they need larger randomized trials before they can be recommended with confidence.^[1] Ask what the evidence is before paying for a course of treatment.

What are the chances it comes back?

About a quarter of treated infections return. Not walking barefoot in public places and disinfecting shoes and socks are thought to lower that risk.^[1]

Does trimming the nail help the medicine work?

Yes. Keeping the nail trimmed and thinned while you are on treatment improves the response.^[1] We can thin thick nails in the office, which also makes shoes more comfortable.

Who should be seen sooner

If you have diabetes, poor circulation or a weakened immune system, fungal nails and the skin around them deserve closer attention, because thick nails can injure the toe and infections can spread. See athlete’s foot and toenail fungus and diabetic foot care.

When to see a podiatrist