Thrush is a yeast (fungus) infection that commonly occurs in the mouths of babies and toddlers. It’s rarely serious but can pass between babies and nursing parents.

It’s typical for a small amount of fungus to live in your mouth. But in some cases, the fungus may rapidly multiply and lead to a yeast infection.

Oral thrush happens when this type of yeast infection develops inside your mouth. It’s also known as oral candidiasis, oropharyngeal candidiasis, or simply thrush.

Oral thrush is more common in babies and older adults, who tend to have weaker immune systems. But it can occur at any age.

Read on to learn about oral thrush, what it can look like, who it affects, what causes it, and how it’s treated.

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In its early stages, oral thrush may not cause any symptoms. But as the infection gets worse, one or more of the following symptoms may develop:

In some cases, oral thrush can affect your esophagus, though this is uncommon. The same fungus that causes oral thrush can also cause yeast infections in other parts of your body.

Learn more about the symptoms of oral thrush.

What are the symptoms of oral thrush in babies?

Oral thrush most often affects infants and toddlers. About 65% of infants have Candida albicans (C. albicans). fungus in their mouths. About 5-7% of babies under one month old will develop the infection.

Babies can contract the fungus from their birthing parent during pregnancy, delivery, or nursing or just from yeast that is naturally present in their environment.

If your baby has oral thrush, it may develop the same signs and symptoms that can affect adults with the condition. It may also cause difficulty feeding and irritability or fussiness.

Read more about thrush in babies, as well as thrush and breastfeeding or chestfeeding.

Oral thrush and other yeast infections are caused by an overgrowth of C. albicans. It exists naturally in the microbiomes of 50% of the population.

It’s typical for a small amount of C. albicans to live in your mouth without causing harm. When your immune system is working properly, beneficial bacteria in your body help keep C. albicans under control.

But if your immune system is compromised or the balance of microorganisms in your body is disrupted, the fungus can grow out of control.

Oral thrush is the most common opportunistic infection in people living with HIV. It can also develop with other conditions or medications that weaken your immune system, such as:

Other risk factors include:

If your immune system is weakened, you’re more likely to develop complications from thrush.

Without proper treatment, the fungus that causes thrush may enter your bloodstream and spread to your heart, brain, eyes, or other body parts. This is known as invasive or systemic candidiasis.

Systemic candidiasis can cause problems in the organs it affects. It can also cause a potentially life threatening condition known as septic shock.

To treat oral thrush, your doctor may prescribe medications. These include:

  • fluconazole (Diflucan)
  • generic nystatin
  • itraconazole (Sporanox)
  • amphotericin B (AmBisome, Fungizone)

Learn more about antifungal medications.

Once you begin treatment, oral thrush usually goes away within a couple of weeks. But in some cases, it can return.

For adults who have recurring cases of oral thrush with no known cause, their healthcare professional will evaluate them for underlying medical conditions that might be contributing to thrush.

Infants may have several episodes of oral thrush in their first year of life.

In addition, your doctor may also recommend some home remedies for oral thrush.

Treatment for babies and nursing parents

If your baby develops oral thrush or you develop a breast or nipple yeast infection, your healthcare professional may advise you to do the following:

  • Treat your baby with antifungal medications and apply an antifungal cream to your breasts. Make sure to wipe the cream off your breasts before nursing.
  • Sterilize your baby’s pacifiers, teething rings, bottle nipples, breast pump pieces, and any other items they put in their mouth.
  • Keep your nipples clean and dry between feedings. If you use nursing pads, avoid those that have a plastic liner, which may trap moisture and create favorable conditions for fungus to grow.

Your doctor may be able to diagnose oral thrush simply by taking a history of your symptoms and examining your mouth for the characteristic lesions that it causes.

They may do a biopsy of the affected area to confirm the diagnosis. They may also do a throat swab culture or endoscopy to see if you have a fungal infection in your throat or esophagus.

If you need help finding a primary care doctor, then check out our FindCare tool.

To reduce your risk of oral thrush, try the following:

  • Avoid sharing cups and utensils with others.
  • Eat a nutritious diet and practice an overall healthy lifestyle to support the functioning of your immune system.
  • Practice good oral hygiene by brushing your teeth twice a day, flossing every day, and visiting your dentist on a regular basis.
  • If your mouth is chronically dry, make an appointment with your doctor and follow their recommended treatment plan.
  • If you have dentures, remove them before you go to bed, clean them daily, and ensure they fit properly.
  • If you have a corticosteroid inhaler, rinse out your mouth or brush your teeth after using it.
  • If you have diabetes, take steps to manage your blood sugar levels.

If you develop a yeast infection in another part of your body other than your mouth, get treatment. In some cases, an infection can spread from one part of your body to another.

Get more tips for managing the risk of yeast infection while breastfeeding or chestfeeding.

Is oral thrush contagious?

Transmission of oral thrush can occur via:

Though C. albicans can pass from one person to another, it doesn’t always cause infection. Also, developing an infection may not mean that you contracted it from someone else, as C. albicans is so common in our environment.

Learn more about how you get thrush.

What should I eat with oral thrush?

Some studies suggest that eating certain probiotic foods or taking probiotic supplements might help limit the growth of C. albicans. However, more research is needed in this area.

Some people believe that limiting or avoiding certain foods may also help curb the growth of C. albicans. The “candida diet” has been developed based on these beliefs. However, this diet lacks scientific support.

It’s a good idea to speak with your doctor or your child’s pediatrician before beginning any supplement of making any dietary changes.

Oral thrush is a yeast infection in the mouth. It most often affects babies but can also occur in adults. Fungi normally live in our mouths, but rapid multiplication can cause an infection.

This is more likely to occur in those with weaker immune systems, but anyone can develop it. If you or your baby develop oral thrush, there are home remedies and medical treatments that can help. It’s usually not a serious infection, but in rare cases can lead to a life threatening blood infection.