Thrush

Topic Overview

What is thrush?

Thrush is a yeast infection that causes white patches in the mouth and on the tongue. Thrush is most common in babies and older adults, but it can occur at any age. Thrush in babies is usually not serious.

What causes thrush?

You get thrush when a yeast called Candida, normally found on the body, grows out of control.

In babies, Candida causes thrush because babies' immune systems are not yet strong enough to control the growth of the yeast. Older people get thrush because their immune systems can weaken with age.

Some people get thrush when they take certain medicines, such as antibiotics or inhaled corticosteroids. People who have certain health problems, such as diabetes or HIV, are also more likely to get thrush.

What are the symptoms?

The most common symptoms of thrush are white patches that stick to the inside of the mouth and tongue.

In babies, it is easy to mistake thrush for milk or formula. It looks like cottage cheese or milk curds. Don't try to wipe away these patches, because you can make them red and sore. Some babies with thrush can be cranky and do not want to eat.

Talk to your doctor if you think you or your child has thrush.

How is thrush diagnosed?

In most cases, doctors can diagnose thrush just by looking at the white patches. Your doctor will also ask you questions about your health. If your doctor thinks that another health problem, such as diabetes, may be related to your thrush, you may also be tested for that condition.

How is it treated?

Thrush is usually treated with prescribed antifungal medicine such as nystatin liquid. In most cases, you will put the medicine directly on the white patches. When a baby has thrush, the yeast can cause a diaper rash at the same time as thrush. Your doctor may prescribe nystatin cream or ointment for his or her diaper area.

To treat thrush in adults, at first you will probably use medicine that goes directly on the white patches. If these medicines don't work, your doctor may prescribe an antifungal pill.

How can you manage thrush?

If your baby has thrush, it may help to:

Clean bottle nipples, pacifiers, toys, and other items that your baby may put in his or her mouth. Boil the items or wash them in warm, soapy water.
Dry your nipples and apply lanolin lotion after breastfeeding. Your doctor may also prescribe a medicine that you can put on your nipples. Breastfeeding mothers and babies can pass a yeast infection back and forth. So both mom and baby need treatment.

If you wear dentures and have thrush, be sure to clean your mouth and dentures every night. You can soak them overnight in a denture cleaner that you buy at the store. Rinse your dentures well after soaking them.

Cause

Candida, the yeast that causes thrush, is normally present in small amounts in the mouth and on other mucous membranes. It usually causes no harm. But when conditions are present that let the yeast grow uncontrolled, the yeast invades surrounding tissues and becomes an infection.

Thrush is most commonly caused by the yeast Candida albicans. Less frequently, other forms of Candida can lead to thrush.

There are many types of bacteria in your mouth that normally control the growth of Candida. Sometimes a new type of bacteria gets into your mouth and disrupts the balance of the organisms already there, allowing Candida to overgrow. Health conditions and other things may also be involved.

How thrush spreads

The yeast that causes thrush can pass from one person to another in different ways.

A newborn can get thrush during birth, especially if his or her mother had a vaginal yeast infection during labour and delivery. Newborns and infants have an immature immune system and have not fully developed a healthy balance of bacteria and yeast in their mouths. Because of this, thrush is common during the first few months of life.
In otherwise healthy toddlers and older children, thrush is usually not contagious. But a child with a weakened immune system may get thrush by sharing toys or pacifiers with a child who has the infection. A child who has thrush spreads the thrush yeast onto anything the child puts in his or her mouth. Another child may then get thrush by putting a contaminated object into his or her mouth.
Adults who wear false teeth (dentures) are at a higher risk for getting thrush and spreading it to others. A person can get thrush by spreading the yeast from their hands to their dentures. And a person with dentures may spread the yeast by handling their dentures and then contaminating an object that another person touches or puts into his or her mouth.

Symptoms

Thrush can be a mild infection that causes no symptoms. If symptoms develop, they may include the following.

In infants

Symptoms of thrush in an infant may include:

White patches inside the mouth and on the tongue that look like cottage cheese or milk curds. Thrush is often mistaken for milk or formula. The patches stick to the mouth and tongue and cannot be easily wiped away. When rubbed, the patches may bleed.
A sore mouth and tongue and/or difficulty swallowing.
Poor appetite. The infant may refuse to eat, which can be mistaken for lack of hunger or poor milk supply. If the infant is unable to eat because of a sore mouth or throat, he or she may act fussy.
Diaper rash, which may develop because the yeast that causes thrush also will be in the baby's stool.

In adults

Symptoms of thrush in an adult may include:

A burning feeling in the mouth and throat (at the start of a thrush infection).
White patches that stick to the mouth and tongue. The tissue around the patches may be red, raw, and painful. If rubbed (during tooth brushing, for example), the patches and the tissue of the mouth may bleed easily.
A bad taste in the mouth or difficulty tasting foods. Some adults say they feel like they have cotton in their mouth.

A breastfeeding mother may get a yeast infection of her nipples if her baby has thrush. This can cause sore, red nipples. She may also have a severe burning pain in the nipples during and after breastfeeding.

What Happens

Most cases of thrush are mild and clear up with the use of an antifungal mouth rinse. Very mild cases of thrush may clear up without medical treatment. It usually takes about 14 days of treatment with an oral antifungal medicine to cure more severe thrush infections. In some cases, thrush may last several weeks even with treatment.

If thrush goes untreated and does not go away by itself, it can spread to other parts of the body.

Thrush can spread to the throat (esophagus), the vagina, or the skin. It rarely spreads to other organs of the body.
Infants can get a diaper rash because the yeast that causes thrush is in the infant's stool.

Thrush is more likely to recur in:

People who use inhaled corticosteroids to treat asthma.
People who take antibiotic medicines for a long time.
People who have false teeth.
People who have a weakened immune system.
Children who put objects contaminated with the thrush-causing yeast into their mouths.

Complications

Complications related to thrush are rare in healthy people but may include:

Poor nutrition for infants who have trouble eating because of thrush.
Infection of the throat.

What Increases Your Risk

There are several things that can increase your risk for getting thrush.

Age

Newborns and infants don't have fully developed immune systems, which increases their risk of developing infections, including thrush.
Newborns are also in the process of developing a healthy balance of bacteria and fungi in their mouths. If this balance is upset, the child may develop thrush.
Older adults, especially those who have serious health problems, are more likely to develop thrush, because their immune systems are likely to be weaker.

Behaviour

The yeast that causes thrush can be spread by oral sex.
Heavy smoking can lower the body's ability to fight off infections, making thrush more likely to develop.

Other conditions

False teeth (dentures), braces, or a retainer that irritates the mouth make it hard to keep the mouth clean and can increase your risk for thrush. An unclean mouth is more likely to develop thrush than is a clean mouth.
People with a weakened immune system, such as those who have diabetes or human immunodeficiency virus (HIV) or who are having chemotherapy treatments, have an increased risk for thrush.
Having a dry mouth (xerostomia) can lead to thrush. Dry mouth can result from overuse of mouthwashes or from certain conditions such as Sjögren's syndrome.
Pregnancy increases your risk for thrush. Hormone changes during pregnancy can lead to thrush by changing the balance of bacteria in the mouth.

Medicines

Medicines that can cause thrush yeast to grow uncontrolled include:

Antibiotics, especially those that kill a wide range of organisms (broad-spectrum antibiotics), such as tetracycline.
Birth control pills (oral contraceptives).
Medicines that weaken the body's immune system, such as corticosteroids.

Environment

Exposure over time to certain environmental chemicals, such as benzene and some pesticides, can weaken the body's immune system, increasing your risk for infections, including thrush.

When should you call your doctor?

Call your doctor today if you or your child has been diagnosed with thrush and:

You have symptoms that show the infection may be spreading, such as white patches on the skin outside of the mouth.
Your symptoms are getting worse or have not improved within 7 days of starting treatment.
Your symptoms come back often.
You have HIV infection, cancer, or another condition that weakens your immune system.

Thrush in an infant's mouth can spread to the breast of the nursing mother. This can cause nipple redness and pain. Contact your doctor if you have redness and pain in the nipples in spite of home treatment or if you have burning pain in the nipple area when you nurse. Your doctor will likely examine your baby's mouth to find out if thrush is causing your symptoms.

Watchful waiting

If you have been diagnosed with thrush before and you believe you may have it again, home treatment may help. Very mild cases of thrush may clear up without medical treatment.

Examinations and Tests

A visual examination is usually all that is needed to diagnose thrush. In addition to looking in your mouth, your doctor will ask you questions about your medical history.

In rare cases, your doctor may order a KOH test in which one of the white patches is scraped and examined. A KOH test is used only in cases when thrush is not clearly evident by visual examination.

A fungal culture may be done when a diagnosed case of thrush is not responding to prescribed medicines.

Treatment Overview

Thrush is a yeast infection that can develop in the mouth and throat and on the tongue. Thrush is most common in newborns, infants, and older adults, but it can occur at any age. In healthy newborns and infants, thrush is usually not a serious problem and is easily treated and cured.

Except for the mildest cases, you should treat thrush to keep the infection from spreading. Prescribed antifungal medicines, which slow down the growth of yeast, are the standard treatment for thrush. Thrush is most commonly treated with medicines that are either applied directly to the affected area (topical) or swallowed (oral).

Mild thrush

In adults, mild cases of thrush may clear up with simple treatment that can be done at home. This treatment usually involves using an antifungal mouth rinse. Treatment usually lasts about 14 days.

Mild thrush in infants is usually treated with topical medicines until at least 48 hours after the symptoms have gone away.

Moderate to severe thrush

More severe thrush infections that have spread to the esophagus are treated with an oral antifungal medicine. A topical antifungal medicine may also be used.

For some severe infections, a treatment period longer than 14 days may be needed.

Persistent or recurrent thrush

Persistent or recurrent cases of thrush may:

Need to be treated twice as long as the symptoms last.
Require treatment with both oral and topical antifungal medicines.

People with weakened immune systems may need to take an antifungal medicine on a continuous basis to prevent thrush infections.

It is very important to get rid of any sources of infection, or thrush will continue to come back. Boil toys, pacifiers, bottles, and other items a child may put in his or her mouth. Or wash the items in warm, soapy water.

It is important to treat conditions that make you more likely to get thrush, such as diabetes, human immunodeficiency virus (HIV), or cancer. For more information, see Prevention.

Prevention

To prevent thrush:

Practice good oral hygiene, including brushing your teeth twice a day and flossing once a day. If you have had a previous thrush infection, replace your toothbrush to help prevent another infection. If you wear dentures, soak them each night in a chlorhexidine solution that you can get from your pharmacist. You can also use a denture cleaner that is sold in most drug or grocery stores. Scrub your dentures with water both before and after soaking them.
Practice good handwashing.
If you are taking a liquid antibiotic, rinse your mouth with water shortly after taking it. If your child is taking a liquid antibiotic, rinse his or her mouth with water after each dose too. Antibiotics can disrupt the balance of bacteria in the mouth and can allow the growth of the yeast that causes thrush.
Get treatment for conditions that increase your risk for thrush, such as diabetes, human immunodeficiency virus (HIV), or cancer.
Use a spacer when taking inhaled corticosteroids, and rinse your mouth after inhaling the dose.

To reduce the risk of spreading thrush to infants:

Treat vaginal yeast infections, especially during the last 3 months of pregnancy. This will decrease your baby's risk of getting thrush during delivery.
Wash bottle nipples and pacifiers daily. And keep all prepared bottles and nipples in the refrigerator to decrease the likelihood of yeast growth.
Do not reuse a bottle more than an hour after the baby has drunk from it, because yeast may have had time to grow on the nipple.
Wash or boil all objects that the baby puts in his or her mouth, or run them through the dishwasher.
Change your baby's diaper soon after it is wet. A wet diaper area provides a good environment for the yeast that causes thrush to grow.
Breastfeed your baby if possible. Breast milk contains antibodies that will help build your baby's natural defence system (immune system) so he or she can resist infection.
Contact your doctor if you are breastfeeding and your nipples become red and sore or you have breast pain during or after nursing your baby. This may be a sign of a thrush infection in your baby that has spread to your nipples.

If your baby needs medicine to treat thrush, don't put the medicine dropper in the baby's mouth. Drop the medicine on a cotton swab and swab it on the affected area. Throw away the swab, and don't put anything back into the medicine bottle that could be contaminated with the yeast.

Home Treatment

Babies and breastfeeding moms

If your child has mild thrush, you may only need to clean bottle nipples and pacifiers regularly and massage the inside of your child's mouth with a clean moist cloth.

If you breastfeed, dry your nipples after breastfeeding. You can also try applying lanolin to your nipples. Your doctor may also prescribe a medicine that you can put on your nipples.

Adults and children (but not newborns)

Drink cold liquids, such as water or iced tea, or eat flavoured ice treats or frozen juices.
Eat foods that are easy to swallow such as gelatin, ice cream, or custard.
If the patches are painful, try drinking from a straw.
Rinse your mouth several times a day with a warm saltwater rinse. You can make the saltwater mixture with 1 tsp (5 g) of salt in 1 cup (250 mL) of warm water.

Adults who wear dentures

If you develop thrush and have false teeth (dentures), it is important to clean your mouth and dentures every night.

Remove your dentures before going to bed.
Scrub them well with a clean toothbrush and water.
Soak them overnight in chlorhexidine, which you can get from a pharmacist. Or you can use a denture cleaner, which you can get from most drug or grocery stores.
Rinse the dentures well in the morning. If you used chlorhexidine to soak your dentures, don't use fluoride toothpaste for at least 30 minutes after putting your dentures back in your mouth. (Fluoride can weaken the effect of chlorhexidine.)

Medications

Prescription medicines that inhibit the growth of yeast (antifungals) are used to treat thrush.

Antifungal medicines are either applied directly to the affected area (topical) so the medicine affects only that area, or swallowed (oral) so the medicine affects the entire body. In rare cases, an antifungal medicine will need to be injected into a vein (intravenous, or IV).

Topical antifungal medicines

Topical antifungal medicines are applied to the affected area and are available in several forms, such as rinses and lozenges.

Topical antifungal medicines need to be in contact with the affected area long enough to stop the growth of the yeast. Lozenges are preferred because they take longer to dissolve. Because the lozenges need moisture to dissolve, sipping water while using them may help them work better.

Because several of the topical antifungal medicines contain sugar, there is an increased risk of cavities when the medicines are used for long periods of time. Using a topical fluoride rinse or gel (if you are not already obtaining fluoride through other means) during treatment may help prevent cavities. Talk to your doctor or dentist before you give your child fluoride products. Too much fluoride may be toxic and can stain a child's teeth.

Oral antifungal medicines (pills)

Unlike topical antifungal medicines, oral antifungal medicines affect the whole body. Your doctor may prescribe a pill if you have a thrush infection in your esophagus. Your doctor may suggest that you use a topical antifungal medicine along with it.

Oral antifungal medicines are used to prevent thrush in certain people with conditions that weaken the body's immune system.

Medicine choices

Polyenes (such as nystatin)
Azoles (such as clotrimazole, fluconazole, and itraconazole)
Chlorhexidine

What to think about

The type of medicine prescribed will depend on your or your child's health, how bad the infection is, how long the infection has been present, and/or whether the infection has come back.
Infants are nearly always treated with topical antifungal medicines. Topical medicines don't work as well in adults, because adults have bigger mouths and it is hard to cover the affected areas.
Both polyenes and azoles cure thrush most of the time.
An azole or nystatin is usually the first medicine used to treat thrush in children.
If thrush does not respond to medicines, your doctor may do a culture test to find out whether drug-resistant strains of yeast are causing the infection.

Credits

Current as of:
September 20, 2021

Author: Healthwise Staff
Medical Review:
John Pope MD - Pediatrics
Anne C. Poinier MD - Internal Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
E. Gregory Thompson MD - Internal Medicine
Thomas Emmett Francoeur MD MDCM, CSPQ, FRCPC - Pediatrics