Warm, damp feet, sweaty trainers and time spent barefoot around pools and changing rooms all give fungi the conditions they love.1
Fungal nail infections are very common, especially on toenails. Around 1 in 4 people may have one at any given time.2 The earlier you act, the more straightforward treatment tends to be. Here are five warning signs worth taking seriously.
Spotted a change in one nail? Acting early, before the infection reaches the base of the nail, gives treatment the best chance.
1. Yellow, white or brown discolouration
Discolouration is usually one of the first visible changes. Parts of the nail may turn yellow, white or brown, often starting at the end of the nail.2
Most infections are caused by a group of fungi called dermatophytes. They usually start at the tip or side of the nail and spread back towards the base, where the nail grows from.2
It's easy to dismiss early discolouration as a bruise, nail polish staining or general wear. If a patch hangs around or keeps spreading over several weeks, get it checked. A fungal infection, an injury and other nail conditions such as psoriasis can look alike. A pharmacist or GP can take a look, and sometimes a nail sample is sent off to confirm the cause.2
It's worth acting at this stage, before the infection reaches the base of the nail. Amorolfine 5% nail lacquers, such as Curanail and Loceryl, are a common first treatment.2 Pharmacy lacquers are for mild infections near the tip or sides of the nail, affecting up to two nails.3
You paint them on once a week, and Loceryl can be used twice a week in some cases. Treatment usually lasts around 6 months for fingernails and 9 to 12 months for toenails.3,4
2. The nail becoming unusually thick
As the infection progresses, the nail often starts to thicken noticeably. Flaky debris can also build up underneath it.2
“A yellow, thickened or crumbly nail can point to a fungal infection, but injury and psoriasis can look similar. Getting it checked before starting treatment helps you treat the right problem. If you have diabetes, poor circulation or a weakened immune system, speak to your GP before treating it yourself.
Ana Carolina GoncalvesSuperintendent Pharmacist
The result is a nail that's harder, denser and more difficult to trim than usual. It may also start to change shape.2
A very thick nail can press on your toe inside your shoe, making walking uncomfortable. If your nails get too tough to cut, a podiatrist can help.5
A noticeably thicker or misshapen toenail can be a sign of fungal infection, but other nail problems can cause it too.2 If it's fungal, it's worth starting treatment sooner rather than later.
If you have diabetes, poor circulation or a weakened immune system, speak to a GP before starting any nail treatment.1,3
Nail lacquers like amorolfine are meant for milder infections. If more than two nails are affected, the infection has reached the base of the nail, or pharmacy treatment hasn't worked, a GP may suggest antifungal tablets instead.1,3 Whichever you use, healthy new nail growing back from the base is the sign the infection has cleared.1
If you get nail lacquer through Pharmica, do not use nail varnish or artificial nails at any point during treatment, until the infection has completely cleared. It isn't known whether the solvents in varnish and glue interfere with treatment, so the manufacturer strongly advises against them. If three or more nails are affected, contact your GP rather than treating it yourself. Review your progress every three months. Carry on if the nail is improving, and talk to a doctor if it looks the same or worse.3
Very thick nail, or more than two nails affected? Ask about antifungal tablets. Nail lacquers suit milder infections.
3. Brittleness and crumbling edges
A healthy nail bends slightly under pressure without breaking. A nail with a fungal infection often becomes brittle and crumbly, so pieces may break off or split at the tip when you file or cut it.1,2
At this stage, the nail is badly weakened. Fungal nail infections don't go away on their own, so it's unlikely to clear without treatment.2
Filing or clipping away the damaged parts of the nail can make it more comfortable. It also helps nail treatments work better.2
Skin around the nail red, swollen or warm? Speak to a pharmacist or GP rather than carrying on with self-treatment.
4. The nail lifting away from the nail bed
When the nail starts to separate from the skin underneath, it's called onycholysis. Infected nails often lift up like this, and sometimes the whole nail can come away.1,2
The nail may look partly detached, and it can snag on socks or clothing, which can be uncomfortable. Trimming a loose nail back to where it's still attached stops it bending or catching.5
Nail lifting can happen with a fungal infection, but also with an injury or other nail problems. The right treatment depends on the cause and how much of the nail is affected.5
If the skin around the nail becomes sore, red, swollen and warm, see your GP promptly rather than waiting.5 This can be a sign of an infection in the skin, which an antifungal lacquer won't treat. Lifting that leaves the skin swollen and painful needs checking too.1
While you're treating it, use your own nail clippers and scissors, and keep a separate file for the affected nails.1,3
Do not share nail clippers, towels or shoes, and never use the same file on infected and healthy nails.
5. Scaly or itchy skin around the nail
Fungal nail infections are often linked to athlete's foot, which is caused by the same group of fungi.2 Itchy white patches between your toes, or dry, flaky skin on your soles, may mean the infection is on your skin as well as your nail.6
The two often happen together, and they can keep each other going if only one is treated.
Left untreated, athlete's foot can spread to your toenails.6 And even after successful treatment, it's common for nails to become reinfected. That's why any affected skin needs treating with an antifungal cream at the same time.2,3 Antifungal creams for athlete's foot are available from pharmacies, and you can use one alongside a nail lacquer.
Not sure what you're looking at? A pharmacist can recommend the right products and help you work out whether it looks more like athlete's foot, a fungal nail infection or both. Getting it right early saves time and means you're treating the right thing.
Frequently asked questions
What is the best fungal nail treatment in the UK?
For mild infections affecting one or two nails, an amorolfine nail lacquer such as Amorolfine, Loceryl or Curanail is a popular first choice from a pharmacy. More widespread or severe infections may need antifungal tablets from a GP. The right option depends on how many nails are affected and how far the infection has spread, so a pharmacist can help you choose.
Curanail contains 5% amorolfine, an antifungal that can be effective for mild nail infections. It’s most effective when the infection is near the tip or sides of the nail and you apply it every single week. Results take time, as healthy nail needs to grow out, usually around 6 months for fingernails and 9 to 12 months for toenails.
Why can Curanail only be used on two nails?
Curanail is licensed for mild infections affecting no more than two nails. If more nails are infected, it usually means a more widespread infection that may need antifungal tablets or a prescription treatment instead. Speak to a pharmacist or GP if three or more nails are affected, or if the infection has reached the base of the nail.
Can I use Curanail twice a week?
Curanail is designed to be applied once a week, so stick to the routine in the leaflet. Its branded equivalent, Loceryl, can be used once or twice a week depending on the advice you’re given. If you’re not sure which routine suits your infection, a pharmacist can talk you through it before you start.
Is tea tree oil good for fungal nail infections?
There isn’t enough good-quality evidence to show tea tree oil can clear a fungal nail infection. Nails are tough, and home remedies often struggle to reach the fungus underneath. A medicated lacquer containing amorolfine, or antifungal tablets from a GP for more severe infections, are more reliable options with clinical evidence behind them.
Will a fungal nail infection go away on its own?
Fungal nail infections rarely clear up without treatment, and they can slowly spread to other nails or get worse. Starting treatment early, while the infection is still mild, gives you the best chance of clearing it with a nail lacquer. If it’s spreading, painful or affecting several nails, speak to a pharmacist or GP.
References
- NHS. Fungal nail infection. NHS website; 2024. nhs.uk
- British Association of Dermatologists. Fungal nail infections. British Association of Dermatologists; 2026. bad.org.uk
- Galderma (U.K.) Limited. Curanail 5% w/v Medicated Nail Lacquer: Summary of Product Characteristics. Electronic Medicines Compendium; 2026. medicines.org.uk/emc
- Galderma (U.K.) Limited. Loceryl 5% w/v Medicated Nail Lacquer: Summary of Product Characteristics. Electronic Medicines Compendium; 2026. medicines.org.uk/emc
- NHS. Nail problems. NHS website; 2024. nhs.uk
- NHS. Athlete's foot. NHS website; 2024. nhs.uk
This article is intended for informational purposes only and does not replace professional medical advice. Always read the patient information leaflet supplied with your medication and speak to a healthcare professional if you have specific concerns.