Fungal Nail Infection (Onychomycosis) guide

What is a fungal nail infection?

A fungal nail infection (onychomycosis) is a very common condition that affects many people at some point in their lives. It is not usually serious but can be unsightly and sometimes difficult to treat. The risk increases with age.

The infection develops slowly. The nail may become discoloured, thickened, and hard to cut. It often starts at the tip of the nail and spreads downwards. If untreated, it may spread to other nails.

What causes it?

Most fungal nail infections are caused by the same fungi that cause athlete’s foot. These fungi can live harmlessly on the skin but multiply in warm, moist, dark environments, such as inside shoes.

Who is more at risk?

You are more likely to develop a fungal nail infection if you:

• Have poor foot hygiene
• Wear closed‑in shoes for long periods
• Walk barefoot in communal areas (showers, pools, gyms, locker rooms)
• Have untreated athlete’s foot
• Have nail trauma or damage
• Have a weakened immune system
• Have conditions such as diabetes, psoriasis, or arterial disease.

Signs and symptoms

In early stages there may be no symptoms. As the infection progresses, you may notice:

• Nail discolouration (white, yellow, orange, brown, or black)
• Thickened, misshapen, brittle, or crumbly nails
• Nails that are difficult to cut
• Pain or discomfort, especially with pressure from footwear
• Surrounding skin may become red, flaky, itchy, cracked, or swollen

If the skin around the nail becomes painful or infected, seek advice from your GP or pharmacist.

Treatment

If the infection is mild or not causing problems, treatment may not be necessary.

Good nail care can help:

• Keep nails trimmed and filed
• Cut nails straight across
• Avoid cutting down the sides of the nail.

NHS podiatry services

Fungal nail infections are not routinely treated by NHS podiatry services. 

NHS podiatry treatment is usually reserved for patients with specific medical needs or high risk conditions, such as diabetes or significant circulation problems.

Medical treatments (via GP or pharmacy)

Medicated nail paints/lacquers (e.g. Curanail®, Loceryl®):

• Suitable for mild or superficial infections
• Available from pharmacies or on prescription
• Applied once or twice weekly
• Can take many months and requires commitment
• Results vary and may not improve nail thickness or shape.

Oral antifungal tablets

Prescribed by your GP if appropriate:

• Nail samples must confirm a fungal infection first
• Taken for at least three months (sometimes up to 9–12 months)
• Blood tests are required before and during treatment.

Treatment is not always successful. Improvement is seen as healthy nail growth from the base. The nail may never return fully to normal.

Reducing your risk

• Maintain good foot hygiene and keep feet dry
• Treat athlete’s foot promptly
• Keep nails well maintained
• Do not share nail clippers, towels, socks, or footwear
• Replace old footwear and socks
• Wear well‑fitting, breathable shoes and change socks daily
• Avoid walking barefoot in communal areas
• Avoid nail injury or trauma.

Our patients matter

Mersey Care NHS Foundation Trust listens and responds to patients and their carers to help improve the services we deliver.

If you have any comments, compliments or concerns you can speak with a member of staff or contact our Patient Advice and Liaison Service (PALS) and Complaints Team

Telephone: 0151 471 2377 
Freephone: 0800 328 2941 
Email: palsandcomplaints@merseycare.nhs.uk