Thrush in your mouth, throat or gut

Oral thrush is an infection in your mouth usually caused by a fungus (yeast) called Candida albicans. It is usually harmless.

Key points about oral thrush

  1. Most people carry candida in their mouths without causing any problems. However, if grows out of control, it can cause a mouth infection called thrush. 
  2. Anyone can develop thrush, but it is more common in babies, older people with dentures and people with weakened immune systems.
  3. Common symptoms include a white or cream-coloured patch in your mouth, painful or sore mouth or throat, redness in your mouth or throat and difficulty eating and drinking.
  4. Oral thrush can usually be treated with antifungal medicine that is applied to your mouth.

See your GP or doctor if you or someone you care for has any of the following:

  • your oral thrush has not resolved despite trying medicines from the pharmacy
  • you have difficulty or pain swallowing
  • your baby is less than 4 months old and has signs of oral thrush.

What are the causes of oral thrush?

Candida (a fungus) usually lives in your mouth without causing any problems. In certain conditions, such as when there is  an underlying condition or the use of some medicines, the candida grows more quickly and creates an infection.

Factors that make you more likely to develop oral thrush include:
  • being a baby or older adult
  • iron deficiency
  • vitamin B deficiency
  • ill-fitting or poorly cleaned dentures
  • smoking
  • inhaled corticosteroids, eg, medicines for asthma or COPD
  • using antibiotics for long periods of time

What are the symptoms of oral thrush?

Oral thrush is usually quite easy to identify by looking in your mouth. Symptoms may include:

  • a white or cream-coloured patch on your tongue, the inside of your cheeks, or the roof of your mouth
  • red, sore or bleeding in the soft patches of your mouth, tongue, throat or roof of your mouth, especially in denture wearers
  • pain or soreness in your mouth or throat
  • red sores and cracks in the corners of your mouth
  • difficulty eating and drinking
  • an unpleasant taste in your mouth.

If you are breastfeeding and your baby has oral thrush, both you and your baby can have symptoms.

For you this can include:

  • red, sensitive or itchy nipples
  • flaky or shiny skin on your areola (the dark area surrounding your nipples)
  • pain in your breast or nipples during or between feeds.

For your baby, this can include:

  • not feeding well
  • having a nappy rash.

How is oral thrush diagnosed?

See your pharmacist or doctor if you think you have any symptoms of oral thrush or you are worried. They will ask you questions about your symptoms, including whether you are taking any medicines or have any underlying medical conditions. They may look into your mouth. Usually no test is needed to diagnose oral thrush, but further testing may be needed if your doctor thinks the thrush has spread to your gut, where it can cause complications.

How is oral thrush treated?

Oral thrush is best treated with antifungal medicines to clear the infection and self-care measures to prevent re-infection. 

Antifungal medicines

Anti-fungal medicines come as a liquid (Nilstat), gel (miconazole) or tablets (Fungilin) that dissolve in your mouth. When using these medicines, it's important to hold them in your mouth before swallowing. Try not to swallow them too quickly, as the longer the medicine is in contact with the site of infection the better. 

Nilstat liquid and miconazole gel can be bought from your pharmacy without a prescription, after discussion with your pharmacist. To ensure you get the right product, your pharmacist will ask you a few questions regarding your symptoms and recommend a suitable product for you. They may refer you to your doctor. 

For more severe infections, a medicine called fluconazole may be used, eg, for people with a poor immune system who develop extensive oral thrush. Fluconazole is usually prescribed for 7 days and this will usually clear oral thrush.

Self-care

  • Babies: Sterilise all feeding equipment, dummies and toys that have been in contact with your baby’s mouth.
  • Breastfeeding: Check if you have a yeast infection on your nipples. Some antifungal medicines can be applied on your nipple to treat the infection.
  • Dentures: Some antifungal medicines can be applied directly to your dentures in the evening and left overnight. 
  • Using a steroid inhaler: Thrush in your mouth is a common side effect. To prevent infection, try using a spacer with your inhaler (read more about spacers). Rinse your mouth with water or clean your teeth after using your inhaler.

How can I prevent oral thrush?

Practicing good oral hygiene is one of the best ways to prevent oral thrush.

  • Brush your teeth twice a day or after each meal.
  • Brush your gums and tongue with a soft toothbrush.
  • Rinse your mouth after eating or taking medicines, especially inhaled corticosteroids.
  • If you smoke, get support to quit.
  • Drink plenty of water, unless you have a health condition that means you need to restrict fluid intake.
  • If your baby has oral thrush, make sure all feeding equipment, dummies and toys that have been in contact with your baby’s mouth are sterilised.
  • If your child has asthma and is on inhaled corticosteroids, use a spacer and rinse their mouth with water afterwards.. 
  • Don’t wear dentures overnight and carefully clean dentures every day as advised by your dentist.
  • Go for regular check-ups with your dentist if you wear dentures.
  • Go for regular check-ups with your doctor if you have diabetes.

Learn more

The following links provide further information about oral thrush. Be aware that websites from other countries may have information that differs from New Zealand recommendations.   

Oral candidiasis DermNet NZ
Oral thrush in newborns – a parent's guide Family Doctor NZ
Oral thrush HealthDirect, Australia
Oral thrush Patient Info, UK
Oral thrush (mouth thrush) NHS, UK

References

  1. Oral candidiasis DermNet NZ
  2. Candidiasis Patient Info, UK
Credits: Health Navigator Editorial Team.