Oral thrush is caused by the fungus Candida albicans. A small amount of this fungus normally lives in your mouth, but is kept in check by your immune system. An infection develops when the fungus overwhelms your body’s ability to control it.
Oral thrush occurs most often in infants and toddlers. White lesions (bumps) on the inner cheeks and tongue are characteristic of this condition.
Antifungal medications can effectively treat oral thrush, and the condition usually does not cause complications for healthy patients. However, oral thrush can be problematic for those with weakened immune systems.
Oral thrush occurs when your immune system can’t maintain its natural defense against the Candida albicans fungus.
Normally, your immune system uses “good” microorganisms to keep Candida albicans and other “bad” microorganisms under control. Taking antibiotics, which kill off the “good” bacteria that would naturally prevent infection, can allow the fungus to multiply.
Diseases such as HIV/AIDS and cancer attack your immune system. Cancer treatments, including chemotherapy and radiation, can damage or kill healthy cells. This also makes you more susceptible to infections such as oral thrush.
Diabetes also can contribute to oral thrush. If you have uncontrolled diabetes, you likely have a high level of sugar in your saliva. Candida albicans can use this extra sugar to fuel its growth in your mouth.
In newborns, oral thrush can be contracted at birth. Women who have vaginal yeast infections can pass the infections to their newborns during delivery because the same fungus that causes yeast infections causes oral thrush.
While babies and toddlers are the most likely to develop oral thrush, people of any age can contract it. You are more susceptible if your immune system is weakened by factors such as:
- having HIV/AIDS, diabetes, or anemia
- taking antibiotics or oral or inhaled corticosteroids
- using chemotherapy, radiation, or drugs to treat cancer
- wearing dentures
- having illnesses that cause dry mouth
- being in overall poor health
- having had an organ transplant
In the initial stages of oral thrush, you may not notice any symptoms. However, as time passes and the fungus grows, the following symptoms may develop:
- white lesions on your tongue, inner cheeks, gums, palate, and/or tonsils
- a creamy, white material on the surface of the lesions
- slight bleeding from the lesions when they are scraped
- mouth pain at the site of the lesions
- dry, cracked skin at the corners of your mouth
- difficulty swallowing if the lesions have spread into your esophagus
In addition, infants may experience difficulty feeding, fussiness, and irritability.
Breastfeeding babies with oral thrush can pass the infection to their mothers. The mother and baby can get caught in a cycle in which they infect and re-infect one another. If you are a breastfeeding mother and your breasts become infected with the fungus, you may experience:
- intense itching, sensitivity, or pain in your nipples
- flaking or shiny skin on the areola (the darker circle of skin that surrounds the nipple)
- severe pain during nursing
- sharp, piercing pain in your breast
For patients with healthy immune systems, complications from oral thrush are rare. Patients whose immune systems are weakened by disease or chemotherapy are the most likely to experience complications. In these patients, the fungus may multiply, enter the bloodstream, and spread throughout the body. The infection can spread to various locations, including the brain, heart, joints, eyes, kidney, liver, or lungs.
Infants who develop oral thrush also may get a severe diaper rash.
In most cases, your physician can diagnose oral thrush by visually examining your mouth and tongue for the characteristic white lesions.
If the diagnosis is not definite, your physician will take a scraping from a mouth lesion for further examination.
If thrush has infected your esophagus, your physician likely will perform more procedures to ensure a correct diagnosis. These techniques may include:
- throat culture (a swab is used to take a tissue sample from the back of your throat for laboratory analysis)
- endoscopy (a camera on the end of a lighted, flexible tube called an endoscope allows your doctor to examine your esophagus, stomach, and small intestine)
Oral thrush in older children and adults can result from an underlying medical condition that may have weakened the immune system. In these cases, your physician will conduct a complete physical examination, along with lab tests, to identify any underlying conditions.
Treatment for oral thrush varies depending on your age and overall health. The purpose of treatment is to prevent the growth and spread of the fungus.
Treatment for oral thrush may consist of:
- clotrimazole lozenge (an antifungal medication that you leave in your mouth until it dissolves)
- nystatin (an antifungal mouthwash that you swish around in your mouth and then swallow)
- fluconazole or itraconazole (oral antifungal medications used for cases that are resistant to initial treatments or for patients who have HIV/AIDS)
- amphotericin B (an oral or intravenous drug used to treat patients with very resistant infections or whose infection has spread to other parts of the body)
Your at-home regimen for treating oral thrush should include:
- brushing with a soft toothbrush to avoid scraping the lesions
- replacing your existing toothbrush regularly until the oral thrush clears up
- not using mouthwashes or sprays
- using a 3 percent hydrogen peroxide solution or saltwater mixture to rinse your mouth
- maintaining appropriate blood sugar levels if you have diabetes
- eating unsweetened yogurt with Lactobacillus acidophilus or taking acidophilus capsules to help restore and maintain healthy levels of “good” bacteria
When a breastfeeding infant has oral thrush, both the mother and infant should be treated to prevent a cycle of reinfection. Treatment in these cases may include:
- using an antifungal medication for the baby and an antifungal cream for the mother’s breasts
- rinsing pacifiers, bottle nipples, and all pieces of a breast pump in a half water/half vinegar solution and allowing the items to air dry
- using nursing pads to prevent the fungus from spreading to your clothes
You may have to wait a couple of weeks to see results after you start treatment for oral thrush. It is common to have a recurrence once the initial infection has healed. A complete cure is more likely if you have a healthy immune system and are free of other diseases.
Because the lesions are painful, oral thrush in infants can cause feeding difficulties. However, the effects are seldom serious in otherwise healthy babies.
You can help prevent oral thrush by following these simple routines:
- Practice good oral hygiene by brushing and flossing your teeth daily. This is especially important if you have diabetes or wear dentures.
- Rinse out your mouth after using a corticosteroid inhaler.
- Add acidophilus capsules or yogurt with Lactobacillus acidophilus to your diet when you are taking prescribed antibiotics.
- Promptly treat a vaginal yeast infection, especially if you are pregnant.
- Avoid foods that are high in sugar and/or yeast, since they could encourage the fungus that causes oral thrush.