How can you prevent oral thrush?

Photo of a dentist and patient (AdamGregor / iStockphoto / Thinkstock)

People who are otherwise healthy don't need to do anything to prevent oral thrush. But it makes sense for people who have a weakened immune system to take specific preventive measures. Research shows that antifungal drugs called antimycotics can help prevent oral thrush. Taking good care of your teeth and the rest of your mouth is also recommended.

Oral thrush is a fungal infection in the mouth and throat area. It is caused by types of yeast fungus called Candida that grow in the mucous membranes lining the mouth and throat. Most people have some of this fungus in the membranes lining their mouth and it doesn’t usually cause any noticeable problems. But under certain conditions the yeast may thrive and lead to an infection. The symptoms of oral thrush include white spots or patches and red inflamed areas in the mouth and throat. It is sometimes painful and may affect your ability to taste food, eat or speak.

The risk of oral thrush is higher in people who have a weakened immune system, for instance due to a chronic disease or cancer treatment. It is also common in people who have HIV/AIDS, and is often quite distressing. Some people end up eating very little because of the pain in their mouth and throat, which can make their body even weaker.

How well do antimycotics prevent fungal infections?

Antimycotics can be used to prevent oral thrush. These drugs kill fungi or reduce their growth. They can also be used as a treatment to prevent a fungal infection from spreading to the rest of your body. There are different types of antimycotics, including nystatin, miconazole, clotrimazole and fluconazole.

Fluconazole is the only drug proven to effectively prevent oral thrush in people who have HIV/AIDS. Fluconazole is taken as a tablet and the drug spreads throughout your entire body – this is known as "systemic" treatment. In older studies, about half of the people with HIV/AIDS developed oral thrush if they didn’t take any preventive measures. Using fluconazole regularly reduced the rate of infection to about one third.

But regular preventive use has its disadvantages, too. For instance, fluconazole can cause headaches, stomach ache and nausea. Taking this medication for months at a time can also lead to fungi becoming resistant to these drugs. Then they aren't as effective when treatment is needed.

During cancer treatment, too, the antimycotics that are most likely to help are those that spread throughout the body. They can be taken as tablets or a syrup, or given as an infusion (drip). Some antimycotic solutions have a local (topical) effect on the inflamed mucous membranes, but also spread throughout the body after they are swallowed. Other antimycotics that are used as ointments, gels or mouthwashes only have a topical effect inside the mouth. These medicines have no proven benefit.

Research summaries

How else can oral thrush be prevented?

There are a number of other recommendations for preventing oral thrush in people who are more likely to get it. But there has been less research in this area, so less is known about their potential benefits – for instance, whether specific oral hygiene measures can in fact prevent oral thrush. But it is generally important to take good care of your teeth and gums, as well as the lining of your mouth, and to avoid injury to that area.

These are the main things you can try:

  • Use a soft toothbrush.
  • Clean the spaces between your teeth: Carefully remove plaque and bits of food, taking care to avoid injury to the mucous membranes.
  • Mouthwash: Many people also rinse their mouth with an antiseptic mouthwash.
  • Go to the dentist: It can be a good idea to visit the dentist before having cancer treatment in the head and neck region so that health problems such as gingivitis can be detected and treated. Your dentist can also help with oral hygiene and oral thrush prevention during and after the cancer treatment.
  • Care for your dentures: If you wear dentures (false teeth), various factors may increase the likelihood of oral thrush. These include things like a poor fit, rough surfaces, leftover food and especially dental plaque. For this reason, dentures should be cleaned regularly, for example with a toothbrush and a special cleaning solution.

In addition to good oral hygiene, it's important to drink enough fluids. People who need nursing care and only drink very little on their own should be offered drinks regularly to keep their mouth from getting dry.

Some people use probiotics to prevent oral thrush. These products are believed to restore a healthy balance of germs in the mouth (oral flora) so that fungi and other harmful germs don’t grow too much. In some studies, probiotics were shown to help prevent oral thrush in older people.