Fungal nail infections

Also called onychomycosis

Fungal infection of the toenails or fingernails can cause discolouration and thickening of nails. Most mild fungal nail infections can safely be left untreated but some people are at risk of complications from nail infections and must seek medical advice.

Key points about fungal nail infections

  1. Fungal nail infections are common and usually affect toenails more often than fingernails.
  2. Most mild fungal nail infections are not serious and can safely be left untreated. 
  3. Some people are at risk of complications from nail infections and must seek medical advice, for example people with diabetes, peripheral vascular disease or connective tissue disease.
  4. Treatment for fungal nail infections is difficult and recurrence is very common. Options include antifungal nail paints that you apply to the nail or antifungal tablets or capsules.

Image credit: Canva

What causes fungal nail infections?

A fungal nail infection occurs when a fungus infects a fingernail, toenail or the skin under the nail (called the nail bed). 

  • You are more likely to get a fungal nail infection if your nail has been damaged through small cuts in the skin around your nail or through the opening between your nail and nail bed. 
  • You can get a fungal nail infection from sharing personal items such as nail clippers, or towels, walking barefoot in public showers or pools, or if you have athletes foot (a fungal infection between the toes), where the fungus spreads from your skin to your nail.  
  • Smoking, having have certain other health conditions, such as diabetespsoriasis or peripheral arterial disease and taking medication that weaken your immune system can increase your risk of getting a fungal nail infection. 

What are the symptoms of fungal nail infection?

A fungal nail infection may not cause any obvious symptoms at first, but as the infection progresses you may notice the following symptoms:

  • Change in colour of some or all of your nail – turns yellow, white, blue, purple or black.
  • Thickening and change in shape of the nail, making it difficult to trim.
  • Pain or discomfort, particularly when using or placing pressure on the affected toe or finger.
  • Brittle or crumbly nails – pieces may break off and come away completely.
  • The skin near the nail may itch, or crack.
  • Separation of the nail from the nail bed. 

Is treatment necessary? 

Most mild fungal nail infections are only a cosmetic issue, not medically serious and can safely be left untreated.

See your pharmacist or doctor for treatment if:

  • the nail/s are painful or they bother you
  • you are at risk of complications (such as cellulitis) from the infection, eg, if you have diabetes, peripheral vascular disease or connective tissue disorders. 

Many nail conditions can look like a fungal infection such as an old injury, a bacterial infection, psoriasis, or onychogryphosis (a condition common in older people where the nail is very thickened but inot due to an infection). Your doctor may take a small sample of your nail to confirm if it really is a fungal infection.

How are fungal nail infections treated?

Fungal nail infections can be difficult to cure. The decision to treat usually depends only on how much it bothers you. If left untreated it probably won’t go away, but it usually won’t cause medical problems.

Your doctor or pharmacist can talk to you about your treatment options. Treatment includes applying medication to the nail such as an antifungal paint or taking antifungal tablets or capsules. Points to consider are:

  • Treatment with antifungals tablets or capsules is only successful for about 75% of people, and the use of antifungal paints is less effective. In other words, cure is not possible for 1 in 4 people, and even higher in elderly people.
  • Even after successful treatment of the fungal infection, the nail may never look completely normal.  
  • There is a 1 in 4 chance that the fungal infection will come back.
  • Treatment is often needed for several months. It can take up to 12 months to confirm successful treatment, due to the slow growth of the nail unit.
  • Treatment is more likely to work with good hygiene practices.

If you are an older person, or you are taking multiple other medications, the risk of treatment may outweigh the benefit. The success of treatment reduces with age and recurrence is very common.

Antifungal nail paints (also called nail lacquer)

  • These treatments are applied directly to the nail, such as amorolfine (Loceryl®) and ciclopirox (Bactrafen®). 
  • They are less effective than taking tablets or capsules and are especially not effective for nails that have thickened.
  • They may be used if you have an infection in only 1 or 2 nails, or if it is not recommended that you take antifungal tablets or capsules.
  • Applying nail paints requires good mobility and eyesight and time to file and cleanse nails before applying them. They will need to be used for at least 6 to 12 months. 

Antifungal tablets or capsules

  • Antifungal tablets or capsules are more effective than paints, especially if the entire nail is infected or if the nail is thickened. Examples of oral medications are terbinafine and itraconazole
  • Antifungal medicine is taken for 6 weeks for fungal infections of the fingernail and for 3 months for fungal infections of the toenail.
  • They are not suitable for people with certain conditions like liver disease or if you are pregnant. They also interact with many other medicines which can increase your risk of side effects. Tell your doctor about all medicines and herbal products you are taking so they can check for interactions (how they could react with each other).

Other treatment options

  • When nails are very thick it can be difficult to cut them and this can cause pain with walking. Reducing the thickness can help with these symptoms. But this doesn’t cure the infection. A podiatrist can help with this but funding is generally only available if you have diabetes. If you don’t have diabetes you can pay privately to see one.
  • Laser treatment is less effective than the paints and oral medications.

How to practise good foot hygiene

Whether you decide to have treatment or not, you should still practise good foot hygiene to stop the infection getting worse or spreading to others.  

  • Keep your nails clean and trimmed. Avoid cutting the cuticles.
  • If your fingernails are affected, avoid repeated hand washing and use of detergents and other chemicals. Wear protective gloves. 
  • If your toenails are affected, good foot care is important – wash and dry your feet well, and check them regularly for cuts and rubs.
  • Treat any other fungal infections such as athletes foot.
  • Keep your feet cool and dry by wearing breathable footwear and cotton socks as fungal infections like warm and damp places.
  • Wear clean socks every day.
  • Avoid high heels and shoes with narrow, pointy toes that may injure your nails.
  • When using shared showers, eg, at the swimming pool, wear protective footwear. 
  • If you need help from a podiatrist (someone who specialises in foot care), your doctor will be able to refer you to one.
  • Don’t share nail clippers and scissors with others.

Take care when getting a pedicure

Having a pedicure can increase your risk of fungal nail infection. Here are some tips to reduce the risk of infection when getting a pedicure:

  • Before you go for a pedicure, it’s important to make sure the salon you choose is clean and that the staff routinely sterilizes the instruments. Speak up about the tools and methods you prefer.
  • Foot baths or bowls should be cleaned with hospital-grade disinfectant between clients.
  • Salon technicians should not tear or cut your skin with the tools they use during a pedicure. Bugs in foot bowls can enter through a cut and cause an infection.
  • If you have broken skin, eg, from a bug bite, scratch or cut, don't use a foot bath.
  • Ask the salon technician to avoid cutting your toenails too short.
  • Having artificial nails increases your risk of nail infections.

Learn more

The following links provide more information about fungal nail infections. Be aware that websites from other countries may have information that differs from Aotearoa NZ recommendations.

Fungal nail infections DermNet NZ
Fungal nail infections NHS Choices, UK
Fungal nail infections Patient Info, UK

References

  1. Management of fungal nail infections BPAC, NZ, 2009
  2. Fungal nail infections DermNet NZ
  3. Fungal skin infections DermNet NZ
  4. Antifungal preparations NZ Formulary
  5. Terbinafine safe prescribing nail it Safer RX 

Information for healthcare providers

Reviewed by

Jeremy Steinberg is a GP with special interests in musculoskeletal medicine, evidence-based medicine and use of ultrasound. He's been reviewing topics for Health Navigator since 2017 and in his spare time loves programming. You can see some of the tools he's developed on his website.

Credits: Health Navigator Editorial Team. Reviewed By: Dr Jeremy Steinberg, FRNZCGP Last reviewed: 22 May 2022