You are getting dressed one morning when you notice it. One of your toenails has turned a bit yellow, or maybe it looks thicker than the others. You start to wonder what you did wrong.
Here is the good news: you did not do anything "wrong". Nail fungus is one of the most common foot problems podiatrists see. The Australian Podiatry Association says around 10% of Australian adults are affected by it. So if you have it, you are far from alone.
In this blog, we explain what causes nail fungus, why it develops, who is more likely to get it, and what you can do about it. We will keep it simple and jargon-free.
What Is Nail Fungus?
Nail fungus is an infection where tiny fungi get into your nail and start to grow there. The medical name is onychomycosis (say it like "on-ee-ko-my-ko-sis"), but most people just call it fungal nails.
It most often affects toenails, but fingernails can get it too. The most common culprit is a group of fungi called dermatophytes. These are the same type of fungi that cause athlete's foot. They feed on keratin, which is the hard protein your nails are made of.
Think of your nail as a roof over a warm, dark, damp room. Once the fungus finds a way in, it has food, shelter and the perfect climate. That is exactly why it can settle in and stay.
The Main Causes of Nail Fungus
There is rarely just one reason. Usually a few everyday things come together. Here are the most common ones.
1. Warm, damp places
Fungus loves moisture and warmth. Your feet spend most of the day inside socks and shoes, which can trap heat and sweat. On a hot Australian summer day, that is basically a fungus holiday resort.
2. Sweaty feet and closed-in shoes
If your feet sweat a lot, or you wear the same shoes every day, your shoes may never fully dry out. Work boots, runners and tight shoes are common trouble spots. Socks that hold moisture make it worse.
3. Walking barefoot in public places
Fungi can live on damp floors. Swimming pool surrounds, gym change rooms, shared showers and even hotel bathrooms are all places where fungus can pass from one person's foot to another. Wearing thongs or pool shoes in these places is a simple way to protect yourself.
4. Athlete's foot that spreads
This one surprises many people. If you have athlete's foot (that itchy, flaky skin between your toes), the same fungus can creep over to your nails. Many cases of nail fungus actually start as untreated athlete's foot.
5. Small injuries to the nail
A stubbed toe, a knock from sport, or years of pressure from tight shoes can leave tiny cracks or gaps in your nail. These openings make it much easier for fungus to slip underneath. Runners, footballers and hikers often see this.
6. Nail salons and shared tools
A pedicure is lovely, but if tools are not cleaned and sterilised properly, they can pass fungus from one client to the next. It is also worth knowing that nail damage from filing or cutting too close to the skin can open the door for infection. If you love getting your nails done, check that your salon cleans its equipment properly, or bring your own tools.
Why Does Nail Fungus Develop and Keep Growing?
That is a fair question. Why does it settle in, and why does it hang around for so long?
There are a few reasons.
Nails grow slowly. Toenails take many months to grow out fully. This means the fungus has a lot of time to spread before you even notice a problem.
The fungus hides under the nail. Because it lives under and inside the nail, it is protected from the outside world. Washing your feet will not reach it. Many creams and sprays also struggle to get through a thick nail.
Your feet get little blood flow compared with the rest of your body. Your toes are the furthest point from your heart, so your body's natural defences do not reach them as easily.
It spreads quietly. At first, there may be no pain and only a small spot of colour change. People often ignore it for months or even years. By then, the fungus has had plenty of time to grow, and the nail may be thick, crumbly or lifting away from the nail bed.
The longer it is left, the harder it usually is to manage. That is why early attention makes a real difference.
Who Is More Likely to Get Nail Fungus?
Anyone can get it, but some people have a higher chance.
Older adults. Nails grow more slowly and become more brittle with age, and circulation often gets weaker.
People with diabetes. Diabetes can affect blood flow and the body's ability to fight infection. Foot problems need extra care in this case.
People with poor circulation. Less blood flow means the body is less able to defend the toes.
People with a weakened immune system. This includes people on certain medications or with certain health conditions.
People with athlete's foot. As mentioned, it often spreads to the nails.
People who are often in wet conditions. Swimmers, gym-goers, cleaners and people who wear gumboots or work boots all day are at higher risk.
People with a family history. Some people seem to be naturally more prone to it, and it can run in families.
Common Signs to Look For
Nail fungus often starts small. Keep an eye out for:
Yellow, brown or white colour changes
A nail that looks thick or bulky
Crumbly or brittle edges
White chalky patches on the nail surface
A nail that has changed shape
A nail that is lifting away from the skin underneath
A bad smell
Mild discomfort when wearing shoes
One important note: not every discoloured nail is fungus. Injuries, psoriasis and other conditions can look very similar. A podiatrist can tell the difference, so it is worth getting it checked rather than guessing.
Common Myths About Nail Fungus
Myth: "It means my feet are dirty." Not true. Clean feet can get nail fungus too. It is about the environment and exposure, not about how often you wash.
Myth: "It is only a cosmetic problem." It can start that way, but over time it can cause thick, painful nails and make walking in shoes uncomfortable. In some people, such as those with diabetes, it can lead to bigger problems.
Myth: "It will go away by itself." It rarely does. Without proper care, it usually stays or slowly gets worse.
Myth: "Nail polish will cover it and fix it." Polish can hide the colour, but it does not treat the fungus. It can even trap moisture under the nail.
How to Lower Your Risk?
You cannot control everything, but these simple habits help a lot:
Dry your feet well after showers and swimming, especially between the toes.
Change your socks daily, and choose breathable ones that keep moisture away from your skin.
Rotate your shoes. Try not to wear the same pair two days in a row, so they have time to dry out.
Wear thongs or pool shoes in public showers, pools and change rooms.
Do not share nail clippers, files or shoes.
Trim your nails straight across and avoid cutting them too short.
Treat athlete's foot early so it does not spread to your nails.
Choose shoes that fit well, with enough room for your toes.
Be careful at nail salons. Make sure tools are properly cleaned.
Small daily habits like these can protect your nails for the long run.
When Should You See a Podiatrist?
It is a good idea to book a visit if:
Your nail has changed colour or shape and is not improving
The nail is thick, painful or hard to trim
The skin around the nail is red, swollen or sore
You have noticed a bad smell
Home remedies have not helped
The problem seems to be spreading to other nails
If you have diabetes, poor circulation or a weak immune system, please do not wait. See a podiatrist as soon as you notice any nail change. Foot problems can get serious faster in these cases.
A podiatrist can confirm whether it really is fungus, explain what is going on with your nails, and suggest a treatment plan that suits you.
Final Thoughts
Nail fungus is common, and it is not a sign that you have done something wrong. It develops when fungus finds a warm, damp spot and a small way in, and then it has plenty of time to settle because nails grow so slowly.
The best things you can do are keep your feet dry, protect them in public places, look after your nails, and get changes checked early.
If you are worried about your nails, the friendly team at Pod Hills is here to help. We will take a close look, explain what is going on in plain English, and guide you through your options. Get in touch with us today to book an appointment, and take the first step to healthier feet.
FAQ’s
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Yes, it can be. It can spread through damp floors, shared nail tools and shared footwear. It can also spread from one of your own toes to another.
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Polish itself does not cause it. However, polish can trap moisture, and damaged nails or unclean salon tools can make infection more likely.
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Yes. Fungus is about warm, damp conditions and tiny openings in the nail, not about cleanliness.
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Colour change, thickening and crumbly edges are common signs, but other conditions such as injury or psoriasis can look similar. A podiatrist can check your nail and confirm what is going on, sometimes with a small nail sample.
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Yes. It can move from one nail to the next, and it can spread to the skin of your feet and cause athlete's foot. Treating it early helps limit the spread.