Fungal nail infections

Also called onychomycosis

Onychomycosis is a common fungal infection of the toenails or fingernails. It can cause discolouration and thickening of one or more nails over a long period of time.

Key points

  1. Fungal nail infections are common as you get older.
  2. To diagnose a fungal nail infection, your doctor may send you to the laboratory to have a nail clipping sample taken. 
  3. Fungal nail infections can be treated with topical treatments that you apply to the nail such as a medicated paint, or oral medication (tablets or capsules).
  4. Treatment of nail infections may not be necessary for everybody. Discuss this decision with your doctor. 


  • A fungal nail infection occurs when a fungus infects a fingernail, toenail or the skin under the nail (called the nail bed).
  • Fungi tend to attack nails that are already 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.  
  • Illness or medication that suppress your immune responses can increase your risk of getting a fungal nail infection. 


Common symptoms of fungal nail infections are:

  • The nail gets thicker.  
  • Change in colour of the nail — turn yellow, white, blue, purple or black.
  • The skin near the nail may itch, or crack.
  • Separation of the nail from the nail bed. 
  • Pain around the nail area.


Many nail problems can look like a fungal infection such as an old injury, a bacterial infection or psoriasis. Therefore it is important to confirm if it really is a fungal infection or not as the treatments are different.

  • To confirm the diagnosis of a fungal infection, you will usually need to have a small sample of nail clipping taken and sent to the laboratory.  
  • This can then be checked to see if a fungus can be grown or seen when viewed by a microscope.
  • The right treatment may depend on knowing which fungus is causing the infection.
  • As fungal infections grow slowly, it can take several weeks to get the results from the laboratory. 


Treatment is not always needed and you should discuss the risks and benefits first with your doctor. Treatment options included applying medication topically to the nail (cream, ointments or paints) or with antifungal medication that you take orally (tablets or capsules). Points to consider are:

  • Treatment with oral antifungals is only successful is about 70% to 80% of people, and topical treatment is less effective. 
  • Even after successful treatment of the fungal infection, the nail may not look completely normal.  
  • There is a 1 in 4 chance that the fungal infection will recur (come back).
  • If you have diabetes, peripheral vascular disease or connective tissue disorders, you are at higher risk of complications (such as cellulitis), if the fungal infections remains untreated, and you may want to consider treating the nail infection.

Topical treatment

  • Topical treatments are applied to the nail such as a medicated nail paint.
  • Examples of topical treatment are amorolfine (Loceryl®), ciclopirox (Bactrafen®) 
  • Topical treatments are less effective than oral medication.
  • They may be used for superficial fungal infections that are not very severe. It can also be used when taking oral antifungals is not desirable or not possible.
  • Topical treatments will need to be used every day for a long period of time, up to 2 years. 

Oral treatment

  • Oral medication is taken for 6 weeks for fungal infections of the fingernail and for 3 months for fungal infections of the toenail.
  • Examples of oral medications are terbinafine and itraconazole. The choice of treatment will depend on the type of fungus causing the infection.
  • Oral antifungal medication interacts with quite a few other medicines, increasing your risk of side effects.

Self care

If you have a fungal nail infection do not share nail clippers or nail files.

  • If the fingernails are affected, avoid repeated hand washing and use of detergents and other chemicals. Wear protective gloves. 
  • If the toenails are affected, good foot care is important.
  • Treat other fungal infections such as athletes foot.
  • Keep the feet cool and dry by wearing breathable footwear and cotton socks.
  • Keep the toenails trimmed.     
  • Avoid high heels and shoes with narrow, pointy toes that may injure the nails.
  • When using communal showers, wear protective footwear. 

Learn more

Fungal nail infections DermNet NZ, 2013
Fungal nail infections NHS Choices, UK

Credits: Sandra Ponen, Pharmacist. Last reviewed: 05 Jun 2015