Toenails that turn yellow, thick or crumbly are often written off as a cosmetic problem. In many cases the cause is a fungal infection. It is common and it tends to be stubborn. Knowing the signs early makes it easier to get the right help.
This article covers what a fungal toenail infection looks like and why it happens. It also explains simple foot care habits that lower the risk. You will find out when a pharmacist, GP or podiatrist should take a look. It is general information to help you look after your feet and nails.
What a fungal toenail infection is
A fungal toenail infection happens when a fungus grows on or in the nail. The medical name is onychomycosis, and you may also hear it called tinea of the nail. According to the Australian Podiatry Association fact sheet on fungal nail infections, around 10 per cent of Australian adults are affected. It is often caused by dermatophytes, which are fungi that live on skin, hair and nails.
Healthdirect information on toenail infections says the condition is common, especially in older people. It often starts when a fungal foot infection spreads to the nail. The most common example is tinea, also known as athlete’s foot. Left untreated, the nail can become deformed or even destroyed.
Signs to look out for
Infected nails may look yellow or brown. They often become thicker than usual and feel crumbly when you cut them. Sometimes the nail starts to lift away from the nail bed. Over time there may be pain or inflammation under the nail, and a bad smell.
Other problems can look similar, which is why a proper check matters. Healthdirect notes that nail injury and psoriasis can cause changes that resemble a fungal infection. A doctor may take a nail scraping for testing. Results can take 5 to 6 weeks, and treatment should wait until they are back.
Why fungal infections take hold
Fungi thrive in warm, moist places. Infection can spread through contact with infected skin or from wet surfaces in public pools and showers. Some people are at higher risk than others. Healthdirect lists these risk factors.
- Sweaty feet
- Spending long periods in closed shoes
- Repeated injury to the toenail
- Diabetes
- A weakened immune system
- Skin conditions such as psoriasis
Sport and fitness can add to the risk when you spend time in damp change rooms. If you plan to try some new and unusual sports, pack a pair of thongs for the showers. That is no reason to stay home. It simply means taking a little more care with your feet.
Foot care habits that help prevent infection
Prevention comes down to keeping feet clean, dry and protected. Healthdirect and the Australian Podiatry Association give very similar advice. Wash your feet often and keep them dry. Keep toenails short and trimmed without sharp edges.
Change into clean cotton socks every day. Choose shoes that fit well and let air move around your feet. Swap between pairs so each one has time to dry out. Wear footwear in public showers and around pool areas.
Sharing is another way infection spreads. Do not share nail scissors, clippers, files or shoes. Wash socks in hot water, and clean shoes with an antifungal spray. If someone at home has an infection, disinfect the shower or bath floor after they use it.
Nail care and appearance
Fungal nails can make people feel self conscious about wearing sandals. It is tempting to cover the problem with polish and hope it fades. Polish only hides the colour and does nothing to treat the infection. Getting the nail checked is the better first step.
Grooming habits tend to work best when they are simple and regular. If fragrance is part of your routine, our piece on choosing scents is worth a read. For feet, the basics are fresh socks each day and shoes that have had time to dry. These habits are easy to keep once they become part of the week.
Infections around the nail
Not every nail problem is a fungal infection of the nail itself. Paronychia is an infection of the skin around the nail. It is usually caused by bacteria, though the herpes simplex virus or a yeast called candida can also be behind it. Healthdirect says it often follows skin damage from picking at nails, an ingrown toenail or a pedicure.
Signs include a painful, red and swollen area beside the nail. There may be yellow pus, and the nail can lift away. Sometimes blisters or a fever appear. Paronychia may need an antibiotic or antiviral medicine, so it is worth seeing a doctor.
Treatment takes patience
Healthdirect explains that most people with a fungal toenail infection need antifungal tablets. These are usually taken for 3 to 6 months or longer. Blood tests may be needed to check liver function during treatment. Creams and ointments usually do not work well on toenails, and laser therapy is less effective.
Even when treatment works, the nail may look abnormal for several months. A healthy new nail takes months to grow. Fingernails grow about three times faster than toenails, so toenails need extra patience. Antifungal cream and good hygiene may help stop the infection coming back.
The Australian Podiatry Association advises following product instructions closely and finishing the full course. See a podiatrist if the problem is not improving or is getting worse. Healthdirect notes that removing the infected nail can sometimes help. Your health professional can explain which options suit you.
Health conditions and your nails
Some people need to take more care with their feet than others. Healthdirect advises people with diabetes or a weakened immune system to see a podiatrist for nail infections. Your general health shows up in other places too, such as your mouth. Our articles on smoking and dental implants and your jawbone and dental implants look at that side of things.
When to see a doctor or podiatrist
A pharmacist is often a good first stop for advice. See a doctor if the pharmacist’s treatment has not worked. You should also get checked if the infection spreads to other toenails. The Australian Podiatry Association suggests seeing a podiatrist at the first sign of infection.
Frequently asked questions
Is a fungal toenail infection contagious?
Yes, it can spread. Fungi pass through contact with infected skin and from wet surfaces like public showers and pool areas. Sharing shoes or nail tools can spread it too. Wearing footwear in shared wet areas helps lower the risk.
Can nail polish cover a fungal nail?
Polish may hide the colour, but it does nothing to clear the infection. Healthdirect says an untreated infection can deform or destroy the nail. It is better to get the nail checked and treated. Ask your pharmacist or doctor before using any products on an infected nail.
Why does treatment take so long?
Antifungal tablets are usually taken for 3 to 6 months or longer. The damaged nail then has to grow out and be replaced by a healthy one. Toenails grow much more slowly than fingernails. That is why the nail can look abnormal for months after treatment.
Should my child see a doctor for a nail infection?
Healthdirect points parents to a GP for toenail and fingernail infections in children. A GP can look at the nail and work out what is causing the change. They can also explain how to care for it at home. Book in sooner if there is redness, swelling or pus around the nail.
This article is general information only and is not medical advice. Speak with your doctor, pharmacist, podiatrist or a qualified health professional about any changes to your nails.
Posted: November 3, 2026 by Health Summit
Fungal Toenail Infections: Signs, Prevention and Care
Toenails that turn yellow, thick or crumbly are often written off as a cosmetic problem. In many cases the cause is a fungal infection. It is common and it tends to be stubborn. Knowing the signs early makes it easier to get the right help.
This article covers what a fungal toenail infection looks like and why it happens. It also explains simple foot care habits that lower the risk. You will find out when a pharmacist, GP or podiatrist should take a look. It is general information to help you look after your feet and nails.
What a fungal toenail infection is
A fungal toenail infection happens when a fungus grows on or in the nail. The medical name is onychomycosis, and you may also hear it called tinea of the nail. According to the Australian Podiatry Association fact sheet on fungal nail infections, around 10 per cent of Australian adults are affected. It is often caused by dermatophytes, which are fungi that live on skin, hair and nails.
Healthdirect information on toenail infections says the condition is common, especially in older people. It often starts when a fungal foot infection spreads to the nail. The most common example is tinea, also known as athlete’s foot. Left untreated, the nail can become deformed or even destroyed.
Signs to look out for
Infected nails may look yellow or brown. They often become thicker than usual and feel crumbly when you cut them. Sometimes the nail starts to lift away from the nail bed. Over time there may be pain or inflammation under the nail, and a bad smell.
Other problems can look similar, which is why a proper check matters. Healthdirect notes that nail injury and psoriasis can cause changes that resemble a fungal infection. A doctor may take a nail scraping for testing. Results can take 5 to 6 weeks, and treatment should wait until they are back.
Why fungal infections take hold
Fungi thrive in warm, moist places. Infection can spread through contact with infected skin or from wet surfaces in public pools and showers. Some people are at higher risk than others. Healthdirect lists these risk factors.
Sport and fitness can add to the risk when you spend time in damp change rooms. If you plan to try some new and unusual sports, pack a pair of thongs for the showers. That is no reason to stay home. It simply means taking a little more care with your feet.
Foot care habits that help prevent infection
Prevention comes down to keeping feet clean, dry and protected. Healthdirect and the Australian Podiatry Association give very similar advice. Wash your feet often and keep them dry. Keep toenails short and trimmed without sharp edges.
Change into clean cotton socks every day. Choose shoes that fit well and let air move around your feet. Swap between pairs so each one has time to dry out. Wear footwear in public showers and around pool areas.
Sharing is another way infection spreads. Do not share nail scissors, clippers, files or shoes. Wash socks in hot water, and clean shoes with an antifungal spray. If someone at home has an infection, disinfect the shower or bath floor after they use it.
Nail care and appearance
Fungal nails can make people feel self conscious about wearing sandals. It is tempting to cover the problem with polish and hope it fades. Polish only hides the colour and does nothing to treat the infection. Getting the nail checked is the better first step.
Grooming habits tend to work best when they are simple and regular. If fragrance is part of your routine, our piece on choosing scents is worth a read. For feet, the basics are fresh socks each day and shoes that have had time to dry. These habits are easy to keep once they become part of the week.
Infections around the nail
Not every nail problem is a fungal infection of the nail itself. Paronychia is an infection of the skin around the nail. It is usually caused by bacteria, though the herpes simplex virus or a yeast called candida can also be behind it. Healthdirect says it often follows skin damage from picking at nails, an ingrown toenail or a pedicure.
Signs include a painful, red and swollen area beside the nail. There may be yellow pus, and the nail can lift away. Sometimes blisters or a fever appear. Paronychia may need an antibiotic or antiviral medicine, so it is worth seeing a doctor.
Treatment takes patience
Healthdirect explains that most people with a fungal toenail infection need antifungal tablets. These are usually taken for 3 to 6 months or longer. Blood tests may be needed to check liver function during treatment. Creams and ointments usually do not work well on toenails, and laser therapy is less effective.
Even when treatment works, the nail may look abnormal for several months. A healthy new nail takes months to grow. Fingernails grow about three times faster than toenails, so toenails need extra patience. Antifungal cream and good hygiene may help stop the infection coming back.
The Australian Podiatry Association advises following product instructions closely and finishing the full course. See a podiatrist if the problem is not improving or is getting worse. Healthdirect notes that removing the infected nail can sometimes help. Your health professional can explain which options suit you.
Health conditions and your nails
Some people need to take more care with their feet than others. Healthdirect advises people with diabetes or a weakened immune system to see a podiatrist for nail infections. Your general health shows up in other places too, such as your mouth. Our articles on smoking and dental implants and your jawbone and dental implants look at that side of things.
When to see a doctor or podiatrist
A pharmacist is often a good first stop for advice. See a doctor if the pharmacist’s treatment has not worked. You should also get checked if the infection spreads to other toenails. The Australian Podiatry Association suggests seeing a podiatrist at the first sign of infection.
Frequently asked questions
Is a fungal toenail infection contagious?
Yes, it can spread. Fungi pass through contact with infected skin and from wet surfaces like public showers and pool areas. Sharing shoes or nail tools can spread it too. Wearing footwear in shared wet areas helps lower the risk.
Can nail polish cover a fungal nail?
Polish may hide the colour, but it does nothing to clear the infection. Healthdirect says an untreated infection can deform or destroy the nail. It is better to get the nail checked and treated. Ask your pharmacist or doctor before using any products on an infected nail.
Why does treatment take so long?
Antifungal tablets are usually taken for 3 to 6 months or longer. The damaged nail then has to grow out and be replaced by a healthy one. Toenails grow much more slowly than fingernails. That is why the nail can look abnormal for months after treatment.
Should my child see a doctor for a nail infection?
Healthdirect points parents to a GP for toenail and fingernail infections in children. A GP can look at the nail and work out what is causing the change. They can also explain how to care for it at home. Book in sooner if there is redness, swelling or pus around the nail.
This article is general information only and is not medical advice. Speak with your doctor, pharmacist, podiatrist or a qualified health professional about any changes to your nails.
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