ConditionSkin, hair & nails
Fungal Nail Infection: Which Treatment Works?
A fungal nail infection (onychomycosis) makes a nail thick, discolored and crumbly, usually a toenail. It is caused by dermatophyte fungi, yeasts or molds. Treatment is slow because the cure only shows as a healthy nail grows out: 6 months for a fingernail and 12 to 18 months for a big toenail. Prescription pills work best, medicated lacquers suit mild cases, and home remedies have little evidence. Confirm it is fungal before treating.
Also called: Onychomycosis, nail fungus, toenail fungus, tinea unguium, candidal nail infection
At a glance
- What it is
- A slow-growing infection of the nail and nail bed by fungi or yeast. Toenails are affected far more often than fingernails.
- How it looks
- Thick, yellow, white or brown nail, crumbly edges, debris under the nail, nail lifting off the bed.
- First step
- Nail clippings sent for testing, since about half of abnormal-looking nails are not fungal.
- Best treatment
- Prescription terbinafine tablets for most moderate to severe cases. Lacquers for mild, early infection.
- Time to clear nail
- 6 months for fingernails, 12 to 18 months for toenails.
When to get help
See a doctor within a day or two
- Redness, warmth and swelling spreading from the toe into the foot, especially with fever (possible cellulitis)
- Any nail problem in someone with diabetes or poor circulation that has a break in the skin, ulcer or pus
- Yellowing skin or eyes, dark urine or severe tiredness while taking antifungal tablets
Book a routine appointment
- A thick, discolored nail that is painful, catching on socks or making walking uncomfortable
- A dark streak or patch under one nail that is growing or spreading onto the skin (needs checking for melanoma)
- Infection that has not improved after a full course of treatment
- Fingernail changes with a red, swollen nail fold
Usually safe to manage at home
- A single mildly discolored toenail edge without pain in an otherwise healthy person, kept short and dry while you decide on treatment
What a fungal nail infection is
Fungi that cause athlete's foot, mainly Trichophyton rubrum, are the usual culprits. They get under the free edge of the nail and spread back toward the cuticle, feeding on keratin, the protein that makes up the nail. The nail thickens, discolors, separates from the bed and crumbles. More detail on the types and risk factors is on our onychomycosis page.
Fungal nail infections become more common with age, and are linked to athlete's foot, sweaty feet, communal showers, tight shoes, nail injury, diabetes, poor circulation, smoking and a weak immune system.
Toenails vs fingernails
| Feature | Toenails | Fingernails |
|---|---|---|
| How common | Much more common | Less common |
| Usual organism | Dermatophytes | Often Candida yeast, especially with wet work |
| Typical clue | Athlete's foot between the toes | Red, swollen nail fold (paronychia) |
| Time to grow a new nail | 12 to 18 months | About 6 months |
| Response to treatment | Slower, more relapses | Better cure rates |
Make sure it is fungal first
Many nail problems look fungal but are not: psoriatic nails, repeated injury from shoes or running, lichen planus, and age-related thickening. Treating a non-fungal nail with months of antifungals wastes time and adds risk. Guidelines advise taking nail clippings and scrapings for:
- Microscopy: shows fungal threads within days.
- Culture: identifies the organism in 2 to 6 weeks.
- PCR testing: faster and more sensitive where available.
A pigmented streak, especially one widening over time or affecting the skin around the nail, needs a doctor to exclude melanoma.
Fungal nail infection treatment options
| Treatment | Best for | Typical course | How well it works |
|---|---|---|---|
| Terbinafine tablets | Moderate to severe toenail or fingernail infection | 6 weeks (fingernails) or 12 weeks (toenails) | Most effective. Complete cure in about half to two-thirds, mycological cure higher |
| Itraconazole tablets | When terbinafine is unsuitable, or for yeast and some molds | Pulsed courses over 2 to 3 months | Effective, more drug interactions |
| Medicated nail lacquer or solution (amorolfine, ciclopirox, efinaconazole, tavaborole) | Mild infection, under about half of the nail, no root involvement | Daily or weekly for 6 to 12 months | Modest. Lower cure rates than pills |
| Laser and light treatments | People who cannot take pills | Several sessions | Evidence weak, results variable, usually not insured |
| Nail removal (chemical or surgical) | Painful, very thick nails, or added to medicine | One procedure | Helps symptoms, combine with antifungal to cure |
| Home remedies (tea tree oil, vinegar, vapor rub) | Not recommended as main treatment | Months | Little reliable evidence |
Antifungal tablets
Terbinafine is the first choice for dermatophyte infections in most guidelines. It is taken daily for 6 weeks for fingernails or 12 weeks for toenails. The medicine binds to the nail and keeps working after you stop, so the nail keeps clearing for months afterward. Your doctor may check liver blood tests, especially if you have liver disease. Tell your doctor about other medicines, since itraconazole in particular interacts with many drugs and is avoided in heart failure. Taste changes, rash and stomach upset can occur with terbinafine.
Topical treatments
Medicated lacquers work best when only the tip of the nail is affected. File and trim the nail regularly so the medicine can penetrate. They are slow, and many people stop before the course is finished, which is the main reason they fail.
Helping any treatment work
- Trim nails straight across and thin thick nails with a file. A podiatrist can do this safely
- Treat athlete's foot at the same time, or the nail will be reinfected
- Keep feet dry, change socks daily, and wear breathable shoes
- Treat or discard old shoes, using antifungal powder inside them
How long does fungal nail treatment take?
The fungus can be killed within the course of treatment, but the damaged nail does not heal. It has to grow out. A healthy band appears at the base of the nail within a few months and slowly advances. Expect about 6 months for a fingernail and 12 to 18 months for a big toenail before the nail looks normal. Judging the treatment as failed too early is a common mistake.
Relapse or reinfection occurs in a sizeable minority of people within a few years. Preventive measures and treating athlete's foot quickly reduce it.
When a fungal nail is more than cosmetic
For most people the problem is cosmetic, with occasional discomfort. In people with diabetes, poor circulation or a weak immune system, a thick broken nail can let bacteria into the skin, leading to cellulitis or foot ulcers. These groups should treat infections and have regular foot checks.
Frequently asked questions
What is the best treatment for a fungal nail infection?
For moderate to severe toenail infections confirmed by testing, terbinafine tablets taken for about 12 weeks give the highest cure rates. Mild infections limited to the tip of the nail may respond to a medicated lacquer used for 6 to 12 months. Combining treatments helps some stubborn cases.
How long does it take to cure a fungal nail infection?
The infection may be cleared within the treatment course, but a normal-looking nail only appears once the damaged part grows out. That takes about 6 months for fingernails and 12 to 18 months for toenails. Keep trimming and wait for clear nail at the base.
Do home remedies work for fungal nail infection?
There is little good evidence that tea tree oil, vinegar soaks, mentholated rubs or baking soda cure nail fungus. Some may slightly improve appearance. They are unlikely to clear an established infection, so they are not a substitute for confirmed testing and medical treatment if you want a cure.
Should I treat a fungal nail infection at all?
Not always. If the nail does not bother you and you are otherwise healthy, leaving it is reasonable. Treatment is advised if it is painful, spreading, affecting your confidence, or if you have diabetes, poor circulation or a weak immune system, because of the risk of skin infection.
Is a fungal nail infection contagious?
Mildly. The fungi spread through damp floors, shared towels, nail tools and shoes, and from athlete's foot on your own skin. Wear sandals in communal showers, do not share clippers, and treat athlete's foot promptly. Close household contacts are sometimes infected with the same fungus.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Dermatology: Nail fungus: diagnosis and treatment
- NHS: Fungal nail infection
- NICE Clinical Knowledge Summaries: Fungal nail infection
- MedlinePlus: Nail fungus
- British Association of Dermatologists: Guidelines for the management of onychomycosis