Oral thrush, also known as oral candidiasis, is a fungal infection that can affect the mouth. Symptoms include a white or yellow buildup on the tongue, an unpleasant taste, and discomfort. Home and medical remedies can treat it.

Oral thrush most commonly occurs due to the fungus Candida albicans. However, Candida glabrata, Candida tropicalis, and Candida krusei can also cause the infection.

For the majority of individuals, oral thrush does not cause any serious problems. However, if a person has a weakened immune system, their signs and symptoms may be much more severe.

This article will cover all aspects of oral thrush, including the causes, symptoms, and treatment.

The Centers for Disease Control and Prevention (CDC) states that doctors treat oral thrush using antifungal medications.

A doctor will prescribe an antifungal medication that a person applies inside of the mouth for mild to moderate oral thrush. These antifungals can include nystatin, miconazole, or clotrimazole. A person will apply the antifungal for 7–14 days.

A doctor may prescribe fluconazole for severe infections or thrush affecting the esophagus. A person can take this medication by mouth, or a doctor will administer it through a vein.

There are other medications available for those who are unable to take fluconazole or if symptoms do not improve after taking it.

For people who also have advanced cancer, a doctor may prescribe 150 mg of fluconazole as a single dose. A doctor will provide a lower dose as the person with cancer has a weakened immune system.

Alongside medical treatment, a person can:

  • rinse the mouth with salt water
  • use a soft toothbrush to avoid scraping the lesions
  • use a new toothbrush every day until the infection has gone
  • avoid using mouthwashes or sprays

The use of steroid inhalers, or corticosteroid inhalers, can increase the chance of developing oral thrush. To help prevent oral thrush from developing, a person can use a spacer or rinse their mouth after use.

Tiny quantities of Candida fungus exist in various parts of our body. It is present in the digestive system, skin, and mouth. Generally, these fungi cause no problems to healthy individuals.

However, people on certain medications, with reduced immune systems, or with certain medical conditions are susceptible to oral thrush when C. albicans grows out of control.

Oral thrush in babies presents as a white coating on the tongue that resembles cottage cheese. A caregiver will not be able to rub the coating off easily. However, they will be able to scrape the coating off, leaving a red area.

Oral thrush in adults generally appears as thick, white, or cream-colored deposits on the mucous membrane of the mouth. The inside of the mouth may appear swollen and slightly red and may feature raised spots.

The white spots may join to form larger ones, also known as plaques. These plaques may then take on a grayish or yellowish color.

If a person scrapes the cream or white-colored deposits, bleeding may occur.

Other symptoms include:

  • cracks at the corners of the mouth
  • an unpleasant taste
  • pain, such as a sore tongue or gum
  • difficulty eating or drinking

Medical professionals sometimes divide oral thrush into three groups based on appearance, although the condition can sometimes sit between categories. The three groups are:

  • Pseudomembranous: A person may develop white to whitish-yellow plaques on the tongue that resemble cottage cheese.
  • Erythematous, or atrophic: The condition appears red raw rather than white.
  • Hyperplastic: Also known as “plaque-like candidiasis” or “nodular candidiasis” due to the presence of a hard-to-remove, solid, white plaque.

According to the CDC, those under 1 month of age have a higher chance of developing oral thrush.

The following can increase the risk of developing oral thrush in adults:

  • Dentures: People who wear dentures are at a higher risk of developing oral thrush. Especially if they do not keep them clean, they own dentures that do not fit properly, or the person does not take them out before going to sleep.
  • Antibiotics: People on antibiotics have a higher risk of developing oral thrush. Antibiotics may destroy the bacteria that prevent the Candida from growing out of control.
  • Steroid medication: Long-term use of steroid medication can increase the risk of oral thrush.
  • Weakened immune system: People with weakened immune systems are more likely to develop oral thrush.
  • Diabetes: People with diabetes are more likely to have oral thrush, especially if they poorly control their disease.
  • Dry mouth: People with less than normal quantities of saliva (xerostomia) are more prone to oral thrush.
  • Smoking: Heavy smokers are more at risk of developing oral thrush. The reasons behind this are unclear.

Other risk factors include:

  • taking inhaled corticosteroid medications for asthma
  • malnutrition, such as iron deficiency and vitamin B12 deficiency
  • cancer treatments, such as chemotherapy

Chemoradiation therapy for head and neck cancer can lead to mucositis, which is when the mouth becomes sore and inflamed. A 2020 study notes that Candidainfection is both a result of chemo-radiation mucositis and a risk factor.

A doctor can look into the person’s mouth and ask some questions about symptoms to diagnose oral thrush.

The doctor may scrape some tissue from the inside of the mouth for analysis.

If the doctor believes that medication or some other underlying cause is behind the thrush, then they will attempt to deal with it accordingly. Treatments in such cases depend on the underlying cause.

The following are commonly asked questions about oral thrush.

Is oral thrush painful?

Some people may find oral thrush painful.

The spots can become raised, and a person may experience discomfort and a burning sensation. In other instances, a person may develop no spots but experience a general soreness in the mouth.

If a person scrapes their spots, they may bleed and experience some mild pain.

Is oral thrush contagious?

Oral thrush is not contagious in adults. However, thrush can pass between an infant and parent during breastfeeding or chestfeeding.

Can oral thrush clear itself?

Without treatment, the symptoms of oral thrush often persist. A person should contact a doctor if they develop oral thrush.

Oral thrush is a fungal infection that develops on the mucous membranes of the mouth.

Common symptoms of oral thrush include thick, white, or cream-colored spots on the mucous membrane. These spots may be raised and can cause some pain and discomfort.

Doctors can treat oral thrush with antifungal drugs, such as nystatin or miconazole. They may also prescribe a topical oral suspension.