Fungal Toenails (Onychomycosis): Causes, Prevention and Treatment

Fungal toenails, also known as onychomycosis, are one of the most common nail conditions seen by podiatrists. They can cause thickened, discoloured, brittle or crumbly nails and may sometimes lead to discomfort or embarrassment.

Although fungal nail infections are rarely serious, they can be difficult to treat and often require patience and consistency.

In this guide, we'll explain what causes fungal toenails, how to prevent them and the treatment options available in the UK.

What Are Fungal Toenails?

Fungal toenails are caused by an overgrowth of microscopic fungi that infect the nail plate, nail bed or surrounding skin.

These fungi thrive in warm, moist environments, which is why toenails are affected far more often than fingernails.

Your feet spend a lot of time:

• Inside socks and shoes

• In warm, enclosed spaces

• Exposed to moisture and sweat

  
  

This creates the perfect environment for fungal infections to develop.

What Causes Fungal Toenails?

Fungal nail infections can develop in two main ways:

1. Contact with Fungi in the Environment

Fungi can be picked up from:

• Public swimming pools

• Showers and changing rooms

• Gym floors

• Hotel carpets

• Nail salons

• Shared towels or footwear

  
  

2. Overgrowth of Fungi Already on Your Skin

Fungi naturally live on our skin without causing problems.

But when conditions are right - warmth, moisture, small nail injuries, reduced immunity - these fungi can overgrow and infect the nail.

Once fungi get under or into the nail, they become very difficult to eliminate.

Are Fungal Toenails Contagious?

Yes, fungal nail infections can spread between people and between different nails on the same foot. They are most commonly transmitted in warm, damp environments such as swimming pools, changing rooms and communal showers.

Can Fungal Toenails Spread to Other Family Members?

Fungal nail infections can sometimes spread between members of the same household, particularly if towels, footwear or bathroom surfaces are shared. However, not everyone exposed to fungal organisms will develop an infection. Factors such as age, circulation, immune function and existing skin conditions can all affect a person's risk.

Can Fungus Live in Shoes?

Yes. Fungal organisms can survive in shoes, especially if they are warm, damp or not allowed to dry properly between uses. This is one reason why fungal nail infections and athlete's foot can sometimes recur even after successful treatment. Rotating footwear, allowing shoes to dry thoroughly and using antifungal shoe sprays or powders may help reduce the risk of reinfection.

What's the Link Between Athlete's Foot and Fungal Toenails?

Athlete's foot and fungal toenails are often closely linked. The same types of fungi that cause athlete's foot can also infect the toenails. In fact, untreated athlete's foot is one of the most common ways that fungal nail infections develop or return. For this reason, if you have both athlete's foot and fungal toenails, it's important to treat both conditions at the same time to improve your chances of successful treatment and reduce the risk of recurrence.

Can Fungal Toenails Go Away on Their Own?

Unfortunately, fungal toenail infections do not usually go away on their own.

This is because the fungi live within and underneath the nail plate, where they are protected from the body's natural immune defences. Toenails also grow very slowly, which means that even if the infection stops progressing, the damaged nail can remain visible for many months.

Without treatment, fungal nail infections may:

• Gradually worsen over time

• Spread to other toenails

• Lead to thickening and crumbling of the nail

• Cause discomfort or pressure in footwear

• Increase the risk of recurring athlete's foot

While some very mild fungal nail infections may remain stable for long periods, most people require treatment if they want to improve the appearance of the nail or prevent the infection from spreading.

The good news is that there are several treatment options available, although all require patience and consistency.

How Long Does It Take to Treat Fungal Toenails?

One of the biggest challenges with fungal toenail treatment is that improvement takes time.

Even when treatment is successful, the damaged portion of the nail will not usually return to normal. Instead, you need to wait for a healthy new nail to grow out and replace the infected nail.

As a general guide:

• Smaller toenails may take around 6–9 months to grow out.

• Big toenails often take 9–12 months.

• In some cases, particularly in older adults, it may take 12–18 months or longer.

This slow growth is one of the main reasons people think their treatment has failed when, in fact, it may be working perfectly well.

For example, if a fungal infection has been successfully treated, you may notice a thin strip of healthy nail gradually growing from the base of the nail. This is often the first sign that treatment has been effective.

It's important to remember that fungal nail treatment is usually a marathon rather than a sprint. Consistency, patience and good foot hygiene are often just as important as the treatment itself.

Common Signs of Fungal Toenails

Fungal nail infections often cause:

• Thickened nails

• Yellow, white or brown discolouration

• Brittle or crumbly nails

• Nails lifting from the nail bed

• Distorted nail shape

• Debris under the nail

• Mild discomfort or pressure in shoes

  
  

Tips for Preventing Fungal Toenails

These simple habits can significantly reduce your risk of fungal infections.

Wash and Dry Your Feet Every Day

Keeping your feet clean and dry is one of the most important preventative steps.

Make sure to dry:

• Between your toes

• Around your nail edges

  
  

Wear Clean Socks Daily

Change your socks every day and after exercise.

Choose natural or breathable fibres such as:

• Cotton

• Bamboo

• Merino wool

  
  

Take a look at Sock Shop for Breathable bamboo socks.

Wear Well-Fitting, Breathable Shoes

Avoid tight shoes and rotate your footwear to allow shoes to dry out fully between wears.

Avoid Walking Barefoot in Public Areas

Wear flip-flops or pool shoes in:

• Public showers

• Changing rooms

• Swimming pools

• Gym facilities

  
  

See a Podiatrist for Regular Check-Ups

Routine podiatry care can:

• Catch fungal infections early

• Reduce nail thickness

• Improve treatment success

• Prevent complications

  
  

How Are Fungal Toenails Treated?

Unfortunately, all fungal nail treatments take time and patience.

This is because you must wait for the infected nail to grow out, which can take:

• 9–12 months for toenails

• Sometimes longer

  
  

1. Oral Antifungal Medication

These tablets must be prescribed by your GP.

Oral antifungal medication is generally considered the most effective treatment for many fungal nail infections.

They are:

• Taken for several months

• Not suitable for everyone

• Monitored with blood tests in some cases

  
  

2. Topical Antifungal Creams or Nail Lacquers

These are applied directly to:

• The affected nail

• The nail bed

• Surrounding skin

  
  

They work best when:

• The nail is thin

• The infection is mild

• Used consistently for many months

Topical antifungal creams and sprays are readily available at most pharmacies or online. We recommend trusted products such as Lamisil and Daktarin.

Athlete's Foot and Fungal Nails: Treatment, Management and Prevention

3. Professional Nail Reduction by a Podiatrist

Reducing nail thickness can:

• Improve the appearance

• Reduce pressure and discomfort

• Allow topical treatments to penetrate better

• Improve treatment success rates

4. Hot Laser Treatment for Fungal Toenails

Laser treatment can be another option for managing fungal toenails - but it’s important to know that not all lasers are the same.

Medical-grade hot laser systems deliver controlled heat into the nail plate and nail bed, which can help damage or destroy fungal organisms.

What to expect:

• The laser is applied directly to the nail using a hand held device

• This raises the temperature in the nail bed

  
  

Laser treatment is:

• Not a guaranteed cure

• Not effective for everyone

• Usually used alongside topical treatments and nail reduction

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Discomfort during treatment:

Hot laser treatment can be uncomfortable due to the heat.

But your podiatrist will:

• Work gradually

• Stop regularly

• Allow the nail to cool between passes

  
  

This makes the treatment tolerable for most patients.

Important points:

• Requires multiple sessions

• Can be costly

• Nails still take months to grow out

• Results vary between individuals

  
  

Laser treatment should only be carried out by a qualified podiatrist or medical professional using a properly regulated medical laser system.

Your podiatrist can advise whether laser therapy is appropriate for your specific type and severity of fungal nail infection.

When Should You See a Podiatrist?

You should book an appointment if:

• Your nails are thick, discoloured or crumbly

• The infection is spreading

• Nails are painful or uncomfortable

• You’re unsure whether it’s fungal

• You have diabetes or poor circulation

• Home treatments aren’t working

  
  

A podiatrist can confirm whether your nail problem is actually fungal and recommend the most appropriate treatment plan.

Final Thoughts

Fungal toenails are extremely common and can often be successfully managed with the right diagnosis, appropriate treatment and patience.

Because toenails grow slowly, treatment can take many months, but consistent management usually leads to improvement over time.

If you are concerned about changes to your nails, seeking professional advice can help ensure you receive the most appropriate treatment.