Foot Health: Managing Toenail Fungus

toenail fungus infection yellow toenails

Fungal infection of the toenails, also known as onychomycosis, is an extremely common issue affecting approximately 1 in 10 people. Read on to find out how to manage this condition.

Infections cause by toenail fungus is more common in adults than in children, and more prevalent in males than in females. In this condition, toenails become discoloured, thick and prone to breakage. It is not typically painful, unless severe.

Onychomycosis can be caused by various fungi, but dermatophytes (a type of mold) are responsible for most infections. Small cracks in the nail or surrounding skin can allow these microorganisms to enter and infect the nail. They feed off the keratin in the nail, the protein which makes nails hard. Toenail fungus is also contagious; you can get it through contact with infected surfaces or from an infected person.

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What Increases Your Risk of Getting Toenail Fungus?

  • Nail injury or trauma: This breaks down the barrier and facilitates fungal invasion of the nails.
  • Occupational hazards: If your job requires your feet to be frequently exposed to moisture (for example: a swimming instructor) or requires you to wear occlusive shoes for a long period of time, it increases your chance of getting toenail fungus. This is because fungi thrive in warm and moist environments
  • Skin conditions: Fungal infection of the foot (also known as athlete’s foot), psoriasis, and hyperhidrosis (abnormally excessive sweating) can also increase your chance of catching a fungal toenail infection. 
  • Other health conditions: weakened immune system e.g. in a patient with HIV infection, diabetes, poor blood circulation e.g. in peripheral vascular disease
  • Ageing: Onychomycosis affects 50% of people older than 70. With age, nails become more brittle and prone to cracks, enabling fungal invasion. Coupled with a weaker immune system and poorer blood circulation, these markedly increase the risk of Onychomycosis.

How To Spot A Toenail Fungus? 

When your toenails develop a fungal infection, the nails are usually:

  • Brittle, cracked, ragged or crumbling
  • Thickened and difficult to trim
  • Discoloured – yellow, brown, or chalky; sometimes dark because of debris accumulating under the nail
  • Detached from the nail bed
  • Slightly foul-smelling 

Onychomycosis is mostly not painful, unless infection becomes severe.

Can Toenail Fungus Be Prevented?

You can take proactive steps to reduce your chances of catching toenail fungus and subsequently infection, for example:

  • Keep your feet clean and dry. Remember fungi love warm and moist environments. 
  • Avoid sharing nail clippers or filers with others as infection happens when your nail contacts with fungi from infected individuals. 
  • Avoid going barefoot and wear flip flops or sandals when walking in warm and moist communal areas like gyms, pools or public showers. 
  • Change to a clean pair of socks everyday and do not re-wear. Sweaty socks increase the risk of catching toenail fungus.
  • If you are prone to fungal toenails infection, you can choose to sprinkle antifungal powder in your shoes. This would prevent fungi from living in your footwear and infecting your toenails. 
  • Alternate your shoes. Give them 24 hours to air and dry before you wear them again. 
  • Keep your nails short and cut them straight across. This reduces the chance of fungi growing under your nails. 
  • Wear proper-fitting shoes: they should not be too tight around the toes as this risks trauma to the nail.

How to Treat Toenail Fungus?

Fungal toenail infection takes a long time to treat, usually between 6 to 12 months. Depending on how many of your nails are infected, the severity and persistence of the infection, you might need topical antifungal medications (meaning creams/ lotions/ lacquer to apply to the nail) and/or oral antifungal medications.

Oral antifungal medications

Oral medications e.g. terbinafine (Lamisil®) and itraconazole (Sporanox®) have a higher complete cure rate and shorter courses of treatment compared to topical medications.  They are recommended if more than 50% of your nails are infected. Although the oral medications stop the growth of the fungus, it still takes months for the infected nails to grow out and get replaced by the healthy nails. 

Typically for toenail fungus, you have to be on oral medication daily for 3 months. Your doctor might also do a blood test before the start of therapy and every 6 weeks to monitor your liver function and ensure it is not affected by the medication. Some other possible side effects of oral antifungals include headache, stomach discomfort or itching. Let your doctor know if you are unable to tolerate any of the side effects. 

Topical antifungal medications 

Topical medications would be preferred if you have a mild infection (with three or fewer nails infected). Your doctor might also prescribe topical medications if you are on existing medications that interact with the oral antifungal medications or if you have a medical condition like liver disease, as you would not be appropriate to be on oral antifungal therapy. 

Commonly used topical antifungal include medicated nail lacquer containing amorolfine (Loceryl®. ) Before using the topical medication, gently file your affected nail with a nail file. Remember not to reuse this nail file on your healthy nails to prevent cross infection. Clean your infected nail with an alcohol swab. Then, use the applicator and coat your infected nail completely with the nail lacquer. Leave the lacquer to dry for 3 to 5 minutes. Try to avoid applying the medication on the skin around the infected nail as it might cause irritation. Typically the nail lacquer has to be used once or twice a week

It can take 9 months and up to a year for complete recovery from toenail fungal infection. After 3 months of topical treatment, healthy nails should be growing out from the base. See a doctor if there is no visible improvement by then.


Fungal toenail infection can be bothersome. Fortunately, there are established treatment options as discussed above. Before starting any of these treatments, you should take note that it can take many months for your nail to look normal again. If you have other medical conditions such as diabetes or if you are immunocompromised, it is best to see a doctor for treatment instead of self-medicating. 

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