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Candidiasis, oral (adults)

Oral thrush is a yeast infection in the mouth, caused by a type of fungus called Candida albicans.

Oral thrush is a yeast infection in the mouth, caused by a type of fungus called Candida albicans. 

It causes an unpleasant taste, soreness, a burning sensation on the tongue and difficulty swallowing. Read more about the symptoms of oral thrush.

Oral thrush is not contagious, meaning it cannot be passed to others.

What causes oral thrush?

Candida albicans fungus is naturally found in the mouth in small amounts. Oral thrush develops when these levels increase. This can be the result of taking certain medications (particularly inhaled steroids), poor oral hygiene, smoking, or a weakened immune system.

Your risk of developing oral thrush is also increased if you:

  • are on a course of antibiotics, particularly over a long period or if you are taking high doses
  • wear false teeth (around seven in 10 people who wear dentures will get oral thrush at some stage)
  • have type 1 diabetes or type 2 diabetes (oral thrush is five times more common in people with severe type 1 diabetes than the population at large)
  • use an asthma inhaler to take corticosteroid medication

Learn more in the causes of oral thrush.

Otherwise healthy newborn babies can also be affected as the condition can be passed from mother to baby during labour if the mother's vagina is infected. It can also be passed through breastfeeding. Learn more in oral thrush in babies.

Treating and preventing oral thrush

Oral thrush can usually be successfully treated with antifungal medicines, delivered in the form of gels, tablets, creams or mouth rinses.

You can reduce the chance of getting oral thrush by:

  • brushing your teeth twice a day
  • having regular dental check-ups
  • keeping your dentures clean
  • stopping smoking

Read more about treating oral thrush and preventing oral thrush.



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Candidiasis, oral (adults)

Symptoms of oral thrush can include sore, white patches (plaques) in the mouth, a painful, burning sensation on the tongue, an unpleasant taste in the mouth, and redness and soreness on the inside of the mouth and throat.

Symptoms of oral thrush can include:

  • sore, white patches (plaques) in the mouth that can be wiped off
  • a painful, burning sensation on the tongue
  • an unpleasant taste in the mouth that can be bitter or salty
  • redness and soreness on the inside of the mouth and throat
  • cracks at the corners of the mouth (angular cheilitis)
  • difficulty swallowing

Dentures

If you wear dentures and have oral thrush, you may develop sore, red areas in your mouth where the dentures have been. This is known as denture stomatitis and can make wearing dentures uncomfortable.

When to seek medical advice

Speak to your GP if you develop symptoms of oral thrush. If left untreated, symptoms will persist and your mouth will continue to feel uncomfortable.



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Candidiasis, oral (adults)

Oral thrush infections are caused by increased levels of Candida albicans fungi, which are naturally present in the mouth.

Oral thrush infections are caused by increased levels of Candida albicans fungi, which are naturally present in the mouth.

This increase may result from:

  • using an inhaler to take corticosteroid medication  
  • certain medications which reduce the amount of saliva produced
  • an injury in the mouth
  • smoking 
  • the immune system being weakened (immunodeficiency)
  • an underlying health condition, such as cancer or HIV

Corticosteroids can be used to reduce inflammation (swelling) and treat a variety of conditions such as:

  • some types of cancer
  • arthritis, a condition that causes inflammation of the bones and joints 
  • eczema,  a long-term skin condition that causes itchy, dry and red cracked skin
  • asthma,  a long-term condition that causes the airways of the lungs to become inflamed and swollen
  • COPD, (chronic obstructive pulmonary disease) a collective name for lung diseases (including chronic bronchitis, emphysema and chronic obstructive airways disease) that cause breathing difficulties

Inhaled corticosteroids are often used to treat asthma. The medicine is delivered through an inhaler, or spacer, (a plastic cylinder attached to your inhaler which increases the amount of medication reaching the lungs and minimising contact with your mouth). Inhaled corticosteroids cause fewer side effects than other forms of treatment but can change acidity levels in the mouth. The change kills healthy bacteria and causes an imbalance that makes oral thrush more likely to develop.

Risk factors

You are at an increased risk of developing oral thrush if:

  • you have diabetes
  • you are a certain age (oral thrush is more common in infants and elderly people) 
  • you have high blood sugar levels
  • you wear dentures that are poorly fitted or not cleaned regularly
  • you often take antibiotics (medication used to fight infections)
  • you have an iron deficiency or B-vitamin deficiency
  • you are having treatment for cancer such as chemotherapy or radiotherapy


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Candidiasis, oral (adults)

In most cases, your GP will be able to diagnose oral thrush simply by examining your mouth. However, some tests may also be used to confirm the diagnosis.

In most cases, your GP will be able to diagnose oral thrush simply by examining your mouth. However, some tests may also be used to confirm the diagnosis.

Your GP may recommend you have a blood test to look for certain conditions associated with oral thrush, such as diabetes and nutritional deficiencies.

biopsy may also be used. This involves taking a sample of the white patches in your mouth to check for the candida fungus under a microscope.

Your GP may also take a swab from the affected area to monitor how the fungus grows over a period of several days.



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Candidiasis, oral (adults)

Oral thrush can be successfully treated with a course of antifungal medicines taken over seven to 14 days.

Oral thrush can be successfully treated with a course of antifungal medicines taken over seven to 14 days.

Antifungal treatments are available in the following forms:

  • gels
  • tablets
  • lozenges
  • powders
  • creams
  • rinses

Rinses are useful for people with a dry mouth who are unable to swallow antifungal tablets.

If you wear dentures, an antifungal cream can be applied to the affected area of the roof of the mouth and to the bottom of the dentures. Antifungal lozenges are also effective. 

Antifungal medicines used to treat oral thrush include:

  • miconazole
  • nystatin
  • fluconazole
  • clotrimazole
  • econazole

If antibiotics or corticosteroids are thought to be causing your oral thrush, the medicine, or the way it is delivered, may need to be changed or the dosage reduced.

Good dental hygiene and not smoking are also recommended.

Some antifungal medications should not be used if you are pregnant, breastfeeding or taking other medications. Always seek advice from your GP or pharmacist before taking antifungal medicines.

Side effects

Possible side effects of antifungal medicines include:

  • nausea (feeling sick)
  • tummy pain
  • diarrhoea 
  • headache
  • indigestion

See the topic about Antifungal medicines for more information about this type of treatment.

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Candidiasis, oral (adults)

Your chances of getting oral thrush are reduced if you keep your mouth clean and healthy.

Your chances of getting oral thrush are reduced if you keep your mouth clean and healthy. You can do this by:

  • rinsing your mouth after meals
  • visiting your dentist regularly for check-ups
  • eating a healthy balanced diet with no more than the recommended amount of sugar
  • keeping your dentures clean
  • brushing your teeth twice a day with a toothpaste that contains fluoride
  • flossing regularly
  • using a mouthwash as part of your routine

Denture hygiene

If you wear dentures it is important to clean them regularly to help prevent yeast from growing.

They should be removed and cleaned every night by brushing with warm, soapy water and scrubbing  the non-polished side of the dentures with a nailbrush.

Dentures can then be soaked in any liquid used to sterilise babies' bottles. However, products containing bleach should not be used on dentures that contain metal.

You should visit your dentist to correct dentures that do not fit properly. This can also reduce the risk of oral thrush and soreness underneath the dentures.

Speak to your dentist for further advice about how to clean your dentures.

Smoking

Smoking encourages yeast growth in your mouth and increases your chance of getting oral thrush.

Speak to your GP if you want to give up smoking. Several treatments are available to increase your chance of quitting successfully, and your GP can put you in touch with local support groups and one-to-one counsellors.

The NHS Smoking Helpline also offers advice and encouragement to help you give up smoking. You can phone the helpline (0800 022 4 332) or visit the NHS Go Smokefree website.

The topic about Quitting smoking also has information and advice about giving up smoking.

Corticosteroids

If you use inhaled corticosteroids as part of your asthma treatment, you can help prevent oral thrush by:

  • rinsing your mouth with water after using your inhaler
  • developing a good technique when you inhale corticosteroids by using a spacer

A spacer is a plastic cylinder which attaches to your inhaler and can help to get the corticosteroid medicine right into your lungs, minimising contact with your mouth.



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