Athlete’s foot and fungal toenails

Athlete’s foot

The fungi that cause athlete’s foot thrive in warm, moist places: sweaty shoes, locker rooms, pool decks and shared showers. Typical signs are itching, burning, scaling and cracking between the toes, or dry, scaly skin across the sole in a “moccasin” pattern; sometimes small blisters form.^[1] Cracked skin between the toes can let bacteria in, which matters especially for people with diabetes.

Other skin problems, including eczema, psoriasis and contact dermatitis, can look like athlete’s foot, so rashes that don’t respond to treatment are worth a closer look.^[2]

Treatment. Topical antifungals work well. In a Cochrane review, both allylamines and azoles cleared far more infections than placebo, and allylamines cleared slightly more than azoles.^[3] Extensive or stubborn infections may need oral medication, which also works: terbinafine and itraconazole were effective in trials.^[7,2]

Prevention. Dry carefully between the toes, change socks daily (and after exercise), rotate shoes so they can dry out, wear sandals in communal showers, and don’t share towels or footwear.^[1]

Fungal toenails

Onychomycosis makes nails thick, yellow or brown, brittle and sometimes lifted from the nail bed. It isn’t only cosmetic: thick nails can press painfully in shoes, and untreated infection can affect quality of life.^[4] Nail damage from repeated minor injury (common in runners) and psoriasis can look just the same, which is why we confirm the diagnosis with a nail sample before recommending months of treatment.^[4,2]

Treatment options:

• Oral antifungals. In a Cochrane review, terbinafine and the azoles were clearly more effective than placebo at clearing toenail infections, and terbinafine is typically preferred.^[5] They need a short check of your health and other medications first.
• Topical lacquers and solutions. Easier to take and useful for milder infections, but they must be applied daily for about a year and clear infection less often.^[6,3]
• Debridement. Thinning a thick nail in the office relieves pressure and pain, and helps topical treatment reach the infection.
• Treating the skin too. Athlete’s foot is often the source of re-infection, so both are treated together.^[2]

Even after successful treatment, the nail looks normal only once it has grown out, which takes 12 to 18 months for a big toenail, and infections can return. Our article on toenail fungus treatment explains what to expect.

Common questions

Is oral medication for toenail fungus safe?

Terbinafine, the usual first choice, is generally well tolerated.^[2] Before prescribing it we review your health and your other medications, because it can interact with some antidepressants, beta blockers and other drugs.^[4] If tablets aren’t right for you, a topical treatment with regular nail thinning is a reasonable alternative for milder infections.

Should I use a cream that combines an antifungal with a steroid?

Generally not. Guidance for doctors now advises against antifungal–steroid combination creams for fungal skin infections, to help treatment work and to limit resistance.^[2] A plain antifungal cream is the better choice for athlete’s foot.

Will the fungus come back?

It can: about a quarter of toenail infections return after treatment. Not walking barefoot in public places and disinfecting shoes and socks are thought to reduce that risk.^[4] Treating athlete’s foot promptly helps too, because the skin infection can re-seed the nails.

What if the treatment isn’t working?

First, we make sure it really is a fungal infection; nails damaged by repeated minor injury or psoriasis look very similar.^[2] Some newer fungal infections are also more stubborn and don’t respond to the usual treatments; they need specialized testing and longer treatment.^[2]

When to seek care