What Is Thrush? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Medically Reviewed
Thrush is a fungal infection that grows in the mouth and throat. It’s also called oropharyngeal candidiasis or oral candidiasis. And it’s the most common human fungal infection, especially among the very young and the elderly.

Normally, small amounts of the fungus, or yeast, known as Candida albicans, reside in the mouth along with various other “good” bacteria. But when Candida albicans grows out of proportion to the mix, thrush can occur. Thrush is usually not serious, but treatment is often important to relieve uncomfortable symptoms.

Signs and Symptoms of Thrush

Thrush isn’t a slow-and-steady type of infection. Instead, it develops quickly. Here are common symptoms:

  • Cottage-cheese-like lesions Creamy white, slightly raised sores often appear on the tongue or inner cheeks, but they can also develop on the roof of the mouth, gums, tonsils, or the back of the throat.
  • Sore mouth
  • Loss of taste
  • Cottony feeling in the mouth
  • Painful swallowing
  • Cracked and red corners of the mouth
  • Bleeding lesions This can occur when the sores are scraped during toothbrushing.
  • Trouble breast- or bottle feeding Infants with thrush may have a hard time feeding.
  • Fussiness and irritability These are symptoms associated with infants with thrush.

Causes and Risk Factors of Thrush

Thrush, whether in the mouth, throat, or esophagus, is not entirely common in healthy adults. Instead, it most often occurs in babies younger than 6 months old and in older adults.

Individuals at an elevated risk of oral candidiasis include:
  • Infants Oral thrush is most common in babies under 1 month old and less common in infants older than 6 months.

  • Pregnant women
  • Those wearing dentures It’s estimated that 50 to 65 percent of people who wear removable dentures get thrush.

  • Smokers This includes users of e-cigarettes (with or without nicotine), according to a study published in January 2019 in the International Journal of Environmental Research and Public Health.

  • Individuals with uncontrolled diabetes
  • Cancer patients
  • Those with HIV/AIDS
  • People experiencing dry mouth
  • Residents in care facilities A report in Postgraduate Medical Journal noted that between 65 and 88 percent of individuals living in acute and long-term care facilities are diagnosed with oral thrush.

In addition, folks who are taking certain medications can raise their chances of developing thrush. These meds include:

Most people who get thrush in the esophagus have weakened immune systems, such as individuals living with HIV/AIDS, or with blood cancers like leukemia.

It’s also important to note that oral thrush is transmittable by way of breastfeeding and kissing.

Oral sexual contact with someone who has a yeast infection can cause oral thrush, too.

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Thrush and Breastfeeding

Babies who have oral thrush can easily pass the infection to their mothers via breastfeeding. Breastfeeding moms who develop yeast infections around the breasts and nipples can just as easily transmit the infection to their babies. Mothers taking antibiotics are especially prone to the infection. Symptoms include:

  • Red, cracked nipples
  • Sensitive, painful, itchy nipples
  • Shiny or flaky skin on the areola
  • Painful nursing
  • Deep, stabbing pain within the breast

“If you are nursing, it’s best to consult your doctor before beginning any antifungals,” says Nina L. Shapiro, MD, the director of pediatric otolaryngology at the David Geffen School of Medicine at UCLA. In all likelihood, you won’t need to stop breastfeeding with thrush. “If your breasts are cleaned in between feedings, and antifungals are being used, you can continue to breastfeed if it’s comfortable,” she says.

How Is Thrush Diagnosed?

Thrush is generally easy to diagnose. Healthcare providers, whether general practitioners or dentists, can usually make the call simply by looking inside the mouth for white lesions. Diagnosis may also involve the following:

  • Scraping the lesions Your practitioner will scrape a small amount of tissue from the lesions and will look for bleeding or examine the specimen under a microscope.
  • Throat culture A provider will swab the back of the throat and examine the microorganisms under a microscope.
  • Endoscopy A tube outfitted with a lighted camera will be passed through the esophagus, stomach, and small intestine. Again, this is reserved for those whose thrush has likely moved to the esophagus.

It’s sometimes important to also test for a possible underlying immunocompromising condition, such as HIV or diabetes.

Duration of Thrush

Once a person begins treatment for thrush, the infection is usually resolved within two weeks. If thrush becomes a recurrent issue, bring it to the attention of your healthcare provider. It may be because of an underlying condition.

Treatment and Medication Options for Thrush

Some babies don't need to be treated for oral thrush, and the infection can be allowed to go away on its own.

But for most others, thrush can — and should — be easily and effectively treated.

Medication Options

Oral candidiasis, whether in the mouth, throat, or esophagus, is most often treated with an antifungal medication that’s applied to the inside of the mouth for up to 14 days.

These antifungals can come in the form of a lozenge or liquid that you swish in your mouth and then swallow. For babies, medication is often applied several times throughout the day with a sponge applicator.

These medications include:

But if the thrush infection is deemed severe — or if it impacts the esophagus — the antifungal medication fluconazole is usually given by mouth or intravenously.

When mothers and breastfeeding infants both develop thrush, both should be treated simultaneously to prevent an ongoing back-and-forth exchange of the infection.

Healthcare providers will also likely recommend an antifungal cream for the infected woman’s breasts.

Alternative and Complementary Therapies

Beyond antifungal medications, healthcare providers may also suggest you take the following steps to help treat the infection.

Use probiotics. Sometimes healthcare providers suggest adding a probiotic as an oral supplement, for example with Lactobacilli or other strains (aka “good” bacteria) or by adding probiotic yogurt to your diet. There’s some evidence to support its use to help rid the mouth of yeast overgrowth and for prevention of thrush.

Brush and floss regularly. Replace your toothbrush often until the thrush infection is gone.

Keep dentures clean and fitting. Remove and clean dentures daily by first soaking, then brushing, with a soft-bristled brush and nonabrasive cleanser. If you use an adhesive, be sure to clean the grooves that fit against the gums. For overnight, soak in water or a mild cleaning solution as recommended by the dentist. See the dentist if dentures become loose.

Rinse with saltwater. To help speed healing, dissolve ½ teaspoon of table salt into 1 cup of warm water. Swish and spit without swallowing.

Try oil pulling. This involves swishing 1 tablespoon of sesame or coconut oil for 15 to 20 minutes, then spitting it out, rinsing, and brushing your teeth. It’s thought that the antifungal properties of the oil may kill yeast. This isn’t advisable for children under 5 years old, and it shouldn’t be the only treatment you take for the infection. If you are thinking about trying this, make sure to discuss it with a healthcare provider first.

Prevention of Thrush

Not all cases of oral thrush can be prevented, but here are some things that you can do to help reduce the chances.

  • Quit smoking.
  • Practice good oral hygiene. Brush teeth at least twice a day; floss at least once a day; see the dentist every six months for cleaning.
  • Treat dry mouth.
  • Control diabetes. When your blood sugar is well-controlled, it can reduce the amount of sugar in your saliva, which discourages the growth of yeast.
  • Rinse your mouth. It’s important to either rinse your mouth or brush your teeth after using a corticosteroid inhaler. “This can clear the residual steroid that may sit on the lips, tongue, or inside the cheeks,” explains Dr. Shapiro.
  • Use a spacer. Teenagers under 16 and older adults should use a corticosteroid inhaler with a spacer if they have asthma. A spacer is a tube with a mouthpiece that sends medicine to the lungs and not to the mouth, tongue, and back of the throat, where it can cause thrush.

  • Clean pacifiers and nipples. If your baby uses a pacifier or bottle, thoroughly clean both in hot water after each use. This helps to avoid reinfection if there is yeast on the pacifier or nipple.

  • Use probiotics. “We’ve found that taking probiotics can help modulate the overgrowth of existing candida, thereby reducing the likelihood of thrush,” says Shapiro. In fact, a study published in September 2015 in the Journal of Dental Research found that twice daily use of probiotics (specifically two strains of Lactobacillus) reduced the prevalence of high candida amounts in elderly nursing-home residents.

Again, oral thrush can be passed through kissing and oral sex with an individual with a yeast infection, so it’s best to avoid these activities if one of you has an active thrush infection.

Complications of Thrush

Thrush usually doesn’t lead to any further health issues or complications. But if you or your baby keeps getting oral thrush, talk with your doctor. This might be a sign of another health issue, or it may signify that your baby's pacifiers or bottles aren’t being properly cleaned to remove the yeast.

In people who have untreated thrush and another underlying condition that weakens the immune system, thrush can spread through the bloodstream or upper gastrointestinal tract, leading to severe infection.

Research and Statistics: How Many People Have Thrush?

Candidiasis in the mouth, throat, and esophagus is uncommon in healthy adults in the United States, but it’s one of the most frequent infections among individuals with HIV/AIDS. In fact, about one-third of people with advanced HIV infections have candidiasis in the mouth and throat, according to the Centers for Disease Control and Prevention (CDC).

Between 4 and 15 percent of babies under 1 year old get oral thrush.

Instances of oral thrush in cancer patients range from 7 to 52 percent.

Thrush and Black Americans

No population is more prone to contracting oral thrush than any other, but Shapiro says, “socioeconomic disparities in oral health [correspond] with disparities in oral thrush.” The authors of a review of 23 studies published in March 2019 in the International Journal of Environmental Research and Public Health cite challenges to accessing treatment, insurance, and the cost of treatment as some of the barriers to oral care within the African American community.

And while no population is more prone to contracting oral thrush, the CDC reports that rates of candidemia — a bloodstream infection that is the most common form of invasive candidiasis — are twice as high in Black Americans as in all other groups. (See below for more on invasive candidiasis.)

It’s not clear exactly what accounts for the difference in rates, but the CDC says that underlying conditions and socioeconomics may play a role.

Related Conditions and Causes of Thrush

Oral thrush is caused by fungi of the genus Candida, which resides normally in the mouth, throat, vagina, and gut. But it can sometimes overgrow and bring about an infection.

A fungal infection caused by candida in the vagina is commonly referred to as a yeast infection.

Invasive candidiasis occurs when candida enters the bloodstream, the brain, eyes, kidneys, heart, bones, or other parts of the body. Unlike the vast majority of thrush and yeast infections, invasive candidiasis is very serious. Candida is one of the main causes of bloodstream infections contracted in American hospitals.

Resources We Love

Here are some additional sources with trusted info on thrush.

KidsHealth From the Nemours Foundation

This nonprofit children’s health system provides readers with easy-to-understand information on a wide variety of health topics. You can find articles on one topic written for different audiences — for parents, for kids, or for teens.

Office on Women’s Health

Thrush is a common breastfeeding issue, but sometimes it’s hard to know what’s thrush and what’s another breast infection or issue. Here, the OWH goes over numerous breastfeeding challenges, including fungal infections, clogged ducts, and mastitis.

American Academy of Pediatrics

The AAP is a professional organization of 67,000 pediatricians that strives to present complicated health and wellness info to parents in a user-friendly manner via its HealthyChildren.org website. The Symptom Checker feature — where parents can click on illustrations to find their way to answers — is especially helpful.

Editorial Sources and Fact-Checking

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