Thrush

Thrush

Also called: Oropharyngeal Candidiasis, Thrush Mouth, Tongue Candidiasis, OPC, Oral Candidiasis, Oral Thrush, Tinea Nigra, Mouth Candidiasis

Summary

Thrush is an infection of the mouth that most often occurs in people with compromised immune systems. It is also extremely common in children under the age of 6 months, but can affect anyone.

A fungus called Candida albicans – more commonly known as yeast – causes the majority of thrush infections. Small amounts of fungi are always present in the mouth, skin and digestive tract. However, certain factors such as illness, medication use or high glucose (blood sugar) levels can alter the environment inside the mouth or throat, causing Candida albicans to multiply rapidly and invade surrounding tissues.

Bad taste in the mouth and decreased taste sensation are usually the first signs of thrush. Eventually, thrush causes symptoms such as creamy, white lesions resembling cottage cheese on the tongue and inner cheeks. It can also affect the gums, tonsils, palate and lips. As time goes on, thrush may become more painful.

Thrush has a distinct appearance. A dentist or physician can usually diagnose the condition by looking for the characteristic white lesions on the mouth, cheeks and tongue. When the physician gently brushes away these patches, it will typically reveal tender, reddened areas that may bleed lightly.

In most cases, thrush is easily treatable and is not viewed as a serious health threat. Mild cases of thrush may be treated by eating unflavored yogurt or taking acidophilus capsules. These cases may disappear within 24 to 48 hours of treatment. Moderate to severe thrush can be treated with antifungal medications, which impede the growth of yeast.

Thrush may be difficult to prevent completely because the fungus is so common. However, patients at increased risk of developing thrush can reduce the likelihood of infection by using antibiotics only as prescribed by a physician. Other tips include seeing the dentist at least twice a year,  brushing and flossing regularly and keeping dentures clean.

About thrush

Thrush is a type of mouth infection caused by an overgrowth of a fungus called Candida, more commonly known as yeast. It is also known as oropharyngeal candidiasis (OPC), oral candidiasis and moniliasis. Thrush can affect the corners of the mouth (cheilitis), insides of cheeks, tongue, palate and/or throat.

There are several types of Candida. However, a variety called Candida albicans causes the majority of thrush infections. Small amounts of these single–celled fungi are always present in the mouth, skin and digestive tract. In most cases, normal bacteria (flora) in the body prevent these fungi from multiplying.

However, certain factors, such as illness, medications or high glucose (blood sugar) levels can alter the environment inside the mouth or throat, causing Candida albicans to multiply rapidly and invade surrounding tissues. An overabundance of this fungus causes symptoms of thrush.

Thrush can affect anyone, but it occurs most often and strikes with greatest severity in people who have compromised immune systems, such as patients with HIV/AIDS or cancer, and those with uncontrolled diabetes. Thrush can also affect babies and toddlers and is extremely common in infants under the age of 6 months. Thrush can be transmitted during a vaginal delivery if the mother has a yeast infection. Symptoms may appear within seven to 10 days after birth. Older children and adults may develop thrush due to various conditions or medications that can promote overgrowth of the Candida fungus.  

Usually, thrush is not passed from person to person through casual contact. It may be transmitted between child and mother through breastfeeding.

Left untreated, symptoms of thrush may become persistent and painful. It can spread to the esophagus (esophagitis), respiratory tracts, lungs and gastrointestinal tract. In rare cases, invasive candidiasis (a condition characterized by infections in the organs and bloodstream) may occur, although this is more common with skin yeast infections. When it does occur, invasive candidiasis may affect the:

  • Heart (endocarditis)
  • Brain (meningitis)
  • Joints (arthritis)
  • Eyes (endophthalmitis)

In most cases, thrush responds well to treatment and is not considered to be a serious medical condition. However, people with weakened immune systems may experience symptoms that are more severe and difficult to control.

Risk factors and causes of thrush

Thrush is caused by the overgrowth of a yeast called Candida albicans. Yeast is a type of fungus that can be found in a person’s intestines, mouth or skin. Fungi typically are normal and helpful to people. They stimulate the immune system, synthesize essential vitamins and protect the body against viruses and bacteria that cause illnesses. The body normally regulates the amount of yeast it has.

However, in some cases yeast can grow uncontrolled and cause thrush. This can occur for a number of reasons. For example, people with compromised immune systems lose the ability to fight off potentially harmful organisms, putting them at higher risk for thrush.

Diseases and therapies that may make a person more vulnerable to thrush infection include:

  • Cancer. Both cancer itself and cancer treatments such as chemotherapy and radiation weaken the immune system, increasing the risk of thrush infection.

  • Certain medications. Thrush may also develop in people who take certain types of medications, including chemotherapy drugs, antibiotics, corticosteroids, birth control pills and drugs to suppress the immune system.

  • Diabetes mellitus. Poorly controlled diabetes can cause sugar levels in the saliva to increase, fostering the growth of thrush.

  • Problems with the immune system. This includes the underdeveloped immunity in infants or declining immunity in the elderly. Chronic diseases can also take their toll on the immune system.

  • Dry mouth (xerostomia). Occurs when the saliva glands fail to produce adequate moisture in the mouth, which disrupts the balance of microorganisms in a person’s mouth. This creates conditions that may be conducive to thrush. Patients who have had radiation treatment to the head or patients with  Sjögren’s syndrome, an autoimmune condition characterized by dry mouth, may be more likely to develop thrush. Certain drugs can also cause dry mouth.

  • Vitamin deficiencies and/or malnutrition. Patients who do not get adequate amounts of vitamins may also have an increased risk of developing thrush.

  • HIV/AIDS. The human immunodeficiency virus (HIV) damages the cells of the immune system, which makes the body more susceptible to infections such as thrush. Thrush rarely occurs in the early stages of AIDS, and usually only occurs when helper T cell counts drop below 350.

  • Vaginal yeast infections. The same fungus that causes thrush also causes yeast infections. Newborn babies sometimes develop thrush after birth when their mothers have vaginal yeast infections at the time of delivery.

  • Certain oral practices. Poorly fitting dentures and the overuse of antiseptic mouthwashes can also increase a patient’s risk of developing thrush.

Thrush is commonly found in infants during the first few months of life. Young children have less fully developed immune systems than adults, so their bodies are less able to control the normal balance of yeast and bacteria. In addition, a baby with thrush can infect the mother’s nipple during breastfeeding.

Pregnancy itself can also cause thrush because the higher levels of estrogen and progesterone alter the balance of bacteria in the woman’s mouth and vagina. Additional factors that can increase the risk of thrush in a nursing mother or her child include a mother’s high sugar diet or low resistance to disease due to fatigue or other health issues.

Other factors that can increase the likelihood of developing thrush include poor general health, malnutrition or smoking.

Signs and symptoms of thrush

Bad taste in the mouth and decreased taste sensation are usually the first signs of thrush. White patches that resemble cottage cheese often develop inside the mouth and typically affect the tongue, palate and corners of the mouth. Patients who try to scratch these white patches may find that the skin becomes red and inflamed, and bleeding may occur. The corners of the mouth may become cracked, red and moist. Thrush can also affect the gums, tonsils and lips.

Initially, thrush may be painless. However, many individuals experience discomfort if the condition progresses, especially if the thrush has spread from the mouth to the palate or throat. Signs and symptoms of thrush can develop suddenly, and may become chronic. In severe cases, lesions may spread into the esophagus (which connects the mouth to the stomach), causing a serious condition called Candida esophagitis. Signs and symptoms of this type of thrush include pain or difficulty swallowing, sensation of food sticking in the throat or the chest, and fever (when the infection spreads past the esophagus).

Thrush is common in newborn babies and may appear about two weeks to a month after birth, or any time in the first six months. In infants, its appearance is often mistaken for milk or formula on the tongue or inner cheeks. Infants may also experience cracked skin in the corners of the mouth, and creamy, white, curd-like lesions on the tongue and inner cheeks.

Babies with thrush may also experience diaper rash as the infection spreads through the digestive tract. Irritability is also common and is most prevalent during feeding due to the mouth pain caused by thrush.

Nursing babies can pass thrush on to their mothers by infecting the nipple during breastfeeding. An infected nipple is likely to be red, cracked and sore, and the skin of the areola may be taut and shiny.

Other symptoms associated with thrush include:

  • A burning sensation in the mouth and throat
  • Low-grade fever
  • Loss of appetite
  • Presence of other illnesses
  • General feeling of sickness

Patients are urged to contact a physician if any of these symptoms appear, or if symptoms have not improved within seven days of beginning the recommended course of treatment.

Diagnosis methods for thrush

In diagnosing thrush, a physician will perform a complete dental examination and compile a thorough medical history. The patient will also likely be asked about any use of antibiotics and medications that suppress the immune system (e.g., chemotherapy drugs, steroids) or about other medications that may be the source of dry mouth.

Thrush has a distinct appearance. A dentist or physician can usually diagnose the condition by looking for the characteristic white lesions on the mouth, cheeks and tongue. When the physician gently brushes away these patches, it will typically reveal tender, reddened areas that may bleed lightly.

Dentists or physicians unable to visually determine whether thrush is present may perform a KOH prep test (a microscopic examination of scrapings from the mouth) to confirm the diagnosis. In some cases, a biopsy will be necessary. In this procedure, a scalpel is used to remove a small piece of tissue that is treated with a special stain and analyzed at a laboratory. 

Patients who have persistent thrush infections may be checked for other illnesses, such as undiagnosed diabetes, cancer or HIV infection. Blood tests or other diagnostic procedures may be performed for this purpose.

Left untreated, thrush can spread into other regions of the body, causing serious complications, such as Candida esophagitis. This condition occurs when thrush extends into the esophagus (which connects the mouth to the stomach).  Diagnosis of Candida esophagitis may require additional tests, including:

  • Throat culture. The back of the throat is swabbed with sterile cotton and the micro-organisms are studied under a microscope.

  • Endoscopy of the esophagus, stomach and small intestines. A flexible camera captures images of the lining of the esophagus and surrounding areas.

  • X-rays of the esophagus. An image of the esophagus is produced with low doses of radiation. In some cases, the patient will swallow a chalky substance called barium that will highlight certain organs more clearly on the x-ray.

Treatment options for thrush

Mild thrush can be treated with simple home remedies. For example, parents can cure mild thrush in children simply by wiping a child’s mouth with a clean, moist cloth. Patients of all ages with mild thrush may be able to cure the infection by consuming unflavored yogurt containing live cultures, which can restore the normal balance of bacterial flora in the body. Acidophilus capsules – found in many natural food stores and pharmacies – work as an alternative to yogurt.

Warm saltwater rinses (one-half teaspoon of salt to 1 cup of water) can help treat thrush. Rinsing the mouth with 1 teaspoon of baking soda to 1 cup of warm water can also be effective. Mild cases of thrush may disappear within 24 to 48 hours of treatment.

Moderate to severe thrush can be treated with antifungal medications, which impede the growth of yeast. In older children and adults, mild cases of thrush can generally be cured with antifungal lozenges or mouthwashes. More severe infections typically require oral antifungal medication (in pill form), which should be taken anywhere from 10 days to two weeks.

All cases of thrush in nursing mothers and their children should be treated. Failure to adequately treat thrush may result in the mother and child repeatedly infecting and reinfecting each other during breastfeeding.

Infants are almost always treated with topical antifungals when medication is necessary. An antifungal cream may also be prescribed to treat any associated diaper rash. Treatments are typically given until 48 hours after the child’s symptoms disappear.

Several steps can be taken to make eating less painful while the patient waits for a thrush infection to subside. These include:

  • Eating easy-to-swallow foods such as gelatin, ice cream and custard

  • Drinking cold liquids and eating flavored ice or frozen juices

  • Using a straw to consume liquids

  • Rinsing the mouth several times a day with warm saltwater

Individuals with severely compromised immune systems, such as those with HIV or AIDS, may require even stronger medications. Individuals with recurrent thrush infections may notice diminished effectiveness of antifungal medications over time and should consult their physician if this occurs.

In some cases, thrush is treated by improving the immune system’s ability to function. For instance, many people with diabetes can cure thrush infections by controlling their glucose (blood sugar) levels.

Most thrush infections disappear within seven to 14 days of treatment. However, recovery from thrush can be more difficult for patients with compromised immune systems. In such circumstances, thrush may spread to affect other areas of the body, including the digestive tract, lungs, liver and skin.

Prevention methods for thrush

Thrush may be difficult to prevent completely because the fungus is so common. However, patients who are prone to thrush can lower their risk of infection by using antibiotics only as prescribed by a physician. In addition, patients who wear dentures should keep their dentures clean, remove them at night, and report any mouth irritation or soreness promptly to a dentist.

Pregnant women are urged to consult a physician if they develop white, cheesy vaginal discharge. Patients who are HIV-positive or who are taking drugs that suppress the immune system may also benefit from taking antifungal drugs on a long-term basis. However, experts disagree about this prevention technique because there is evidence that Candida fungi may become resistant to the medications.

In addition, patients who take medications that cause dry mouth may be switched to a similar drug that is less likely to cause this side effect. If this is not possible, or for patients who regularly experience dry mouth symptoms, a physician may suggest they drink more water and use a mouth moisturizer or saliva replacement formula.

Various measures can also be undertaken to help prevent thrush in infants. Soaking bottle nipples and pacifiers daily in hot tap water that is at least 130 degrees Fahrenheit (54.4 degrees Celsius) is one method.

Other tips for reducing the risk of thrush include:

  • Visit the dentist regularly – at least twice a year. Brush and floss regularly and keep dentures clean. Regularly brushing the tongue is important, as well.

  • Consume unflavored yogurt or acidophilus capsules when taking antibiotics.

  • Try to quit smoking.

  • Limit the amount of sugar and yeast-containing foods that are consumed. These include bread, beer and wine.

  • Breastfeed babies to help build their natural defense systems. Mothers with fungal infections are also urged to use nursing pads, which can prevent the fungus from spreading to the clothes. These pads should not have a plastic barrier.

  • Avoid mouthwashes or sprays. These can destroy the normal flora in a person’s mouth.

Questions for your doctor regarding thrush

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following thrush-related questions:

  1. What signs should I look for that might indicate I have thrush?
  2. If I spot signs of thrush, should I try to treat it myself before seeing a dentist or doctor?
  3. How will you diagnose my thrush?
  4. What do you suspect is causing my thrush?
  5. What are my treatment options? How long will the treatments last?
  6. What should I do if my treatments do not appear to be working?
  7. Do you recommend using antifungal medications? What are the risks?
  8. What should I do if my infection returns?
  9. What foods should I eliminate from my diet that might reduce the risk of thrush?
  10. What other prevention steps can I take?
Scroll to Top