Oral thrush is a yeast infection of the tongue and the lining of the mouth. It is common, usually easy to recognize, and treatable. It also tends to show up when something else in the body has changed, such as a course of antibiotics, a weakened immune system, high blood sugar or poorly fitting dentures. This guide explains what thrush is, who is most likely to get it, how it is diagnosed and treated, and what you can do to lower the chance it comes back.
What causes thrush
MedlinePlus explains that a small amount of a fungus called Candida normally lives in the mouth. It is usually kept in check by your immune system and by the other germs that share the mouth. Thrush happens when that balance is upset and too much of the fungus grows, either because the immune system is weak or because normal bacteria die off.
The ADA describes thrush (also called candidiasis or moniliasis) as a fungal infection that occurs when the yeast Candida albicans reproduces in large numbers.
Who is more likely to get it
MedlinePlus lists several situations that make thrush more likely:
- Being in poor health or being very old. Young babies are also more likely to get thrush.
- Having HIV or AIDS
- Receiving chemotherapy or medicines that weaken the immune system
- Taking steroid medicine, including some inhalers used for asthma and COPD
- Having diabetes with high blood sugar
- Taking antibiotics, which kill some of the healthy bacteria that normally keep Candida from overgrowing
- Wearing dentures that do not fit well
The ADA adds that thrush is common among denture wearers and that people with dry mouth are also susceptible. If dry mouth is part of the picture, our guide to dry mouth and your teeth covers causes and what helps.
Symptoms to look for
According to MedlinePlus, symptoms include:
- White, velvety sores in the mouth and on the tongue
- Some bleeding when you brush your teeth or scrape the sores
- Pain when swallowing
Thrush in newborns, MedlinePlus notes, is somewhat common and easy to treat. If you are caring for a baby with white patches in the mouth, check with the child’s doctor.
How thrush is diagnosed
A health care provider or dentist can usually diagnose thrush by looking at the mouth and tongue, because the sores are easy to recognize. To confirm it, MedlinePlus says a provider may gently scrape a sore and examine the sample under a microscope.
In severe cases thrush can spread into the esophagus, the tube that connects the mouth to the stomach. If that is suspected, a provider may take a throat culture or look at the esophagus and stomach with a flexible, lighted scope.
Treatment
Mild cases after antibiotics
For mild thrush after antibiotics, MedlinePlus suggests eating yogurt or taking over-the-counter acidophilus pills, which may help restore a healthy balance of germs in the mouth.
Prescription treatment
For a more severe case, MedlinePlus says a provider may prescribe:
- An antifungal mouthwash (nystatin)
- Lozenges (clotrimazole)
- Antifungal medicine taken as a pill or syrup, such as fluconazole or itraconazole
Which option is right depends on how severe the infection is and on your overall health, so follow your provider’s instructions and finish the full course.
Treating the underlying cause
The ADA emphasizes that controlling candidiasis means preventing or controlling the condition behind the outbreak. That might mean better blood sugar control, a review of medicines, attention to dry mouth or a denture adjustment. When dry mouth cannot be cured or avoided, the ADA notes that saliva substitutes and prescription medications may help.
Outlook and possible complications
MedlinePlus says oral thrush can be cured. If your immune system is weak, though, thrush may come back or cause more serious problems. In people with a weakened immune system, Candida can spread through the body and cause a serious infection that may affect the brain, esophagus, eyes, heart or joints. That is why people in higher-risk groups should not ignore symptoms.
When to contact a professional
MedlinePlus recommends contacting your provider if:
- You have thrush-like sores
- You have pain or difficulty swallowing
- You have symptoms of thrush and are HIV positive, receiving chemotherapy, or taking medicines that suppress your immune system
Not every white patch in the mouth is thrush. A dentist can check sores that look unusual or do not clear up, and our oral cancer screening guide explains what that exam involves.
Prevention tips
Daily oral hygiene
The ADA calls good oral hygiene essential. Brush and clean between your teeth every day, and keep up with regular dental visits.
If you wear dentures
The ADA advises cleaning dentures to remove Candida and taking them out at bedtime. Because MedlinePlus lists poorly fitting dentures as a risk factor, ask your dentist to check the fit if dentures feel loose or cause sore spots. Our guide to full vs partial dentures covers the basics of denture types.
If you have diabetes
MedlinePlus says people with diabetes can help prevent thrush by keeping good control of their blood sugar. Read more in our guide to diabetes and oral health.
If you use a steroid inhaler
Some asthma and COPD inhalers are a listed risk factor. Ask your doctor or pharmacist how to use your inhaler in a way that lowers the chance of thrush.
If it keeps coming back
MedlinePlus notes that for people who get thrush often, a provider may recommend taking antifungal medicine regularly to keep it from returning.
Questions to ask at your appointment
- Is this thrush, or could it be something else that needs a different test?
- Is one of my medicines, inhalers or my denture fit likely contributing?
- How long should treatment take to work, and what should I do if it does not?
- Should my blood sugar, immune health or saliva flow be checked?
- How should I clean my dentures, toothbrush or other mouth appliances while I am being treated?
Writing down when symptoms started, any recent antibiotics, and every medicine you take will make the visit more useful.
Frequently asked questions
Is oral thrush contagious?
The sources used for this article focus on overgrowth of a fungus that normally lives in the mouth, rather than on catching it from someone else. If you have concerns about spreading it, for example while breastfeeding, ask your doctor.
Can antibiotics cause thrush?
Yes. MedlinePlus explains that antibiotics kill some of the healthy bacteria that keep Candida in check, which can let the fungus overgrow.
Can I scrape the white patches off?
MedlinePlus notes that scraping the sores can cause some bleeding. Leave diagnosis and treatment to your dentist or doctor instead of trying to remove patches yourself.
Should a dentist or a doctor treat thrush?
Either can usually diagnose it by looking at your mouth. Your doctor may be the better first call if you have an underlying condition such as diabetes, HIV or cancer treatment. Your dentist is a good first call if you wear dentures. If you need a dentist, you can search for one near you.
Does thrush go away on its own?
Mild cases after antibiotics may improve with simple steps such as yogurt or acidophilus, according to MedlinePlus. Persistent or painful thrush, or thrush in someone with a weakened immune system, needs professional care.
Sources
By the Dentist Review Editorial Team.
This article is for general information only and is not medical advice. Talk to a licensed dentist about your own situation. See our disclaimer.
Featured image: “Dentist Examining Patient’s Teeth with Dental Mirror” by Jameswasswa, via Wikimedia Commons, licensed CC BY-SA 4.0. Resized and compressed for the web.
Our guides are written and reviewed by the Dentist Review editorial team. We research each topic using public, authoritative sources such as the CDC, the National Institutes of Health (NIH/NIDCR), the American Dental Association (ADA) and CMS, and we update guides when guidance changes. Guides are for general information only and are not dental or medical advice; please read our disclaimer and learn more about us.