Tongue thrush, also called oral thrush or oral candidiasis, is a fungal infection that produces creamy white patches on the tongue, inner cheeks, gums, or roof of the mouth. It’s caused by an overgrowth of Candida, a type of yeast that normally lives in your mouth in small amounts. When the balance of microorganisms in your mouth shifts, Candida can multiply out of control and form visible lesions.
The patches often look like cottage cheese and can usually be scraped off, revealing reddened, sometimes bleeding tissue underneath. Thrush is common in babies and older adults, but it can affect anyone whose immune system or oral environment gives the fungus an opening.
What It Looks and Feels Like
The signature sign is raised white or yellowish-white patches on the tongue or other soft tissues inside the mouth. These patches have a slightly bumpy, curd-like texture. If you try to wipe or scrape them away, the area underneath is typically raw, red, and may bleed lightly.
Beyond the visible patches, thrush can cause a cottony feeling in your mouth, soreness or burning (especially while eating), redness at the corners of the lips, and a diminished sense of taste. Some people describe a persistent unpleasant taste. Eating acidic or spicy foods tends to make the discomfort worse. In mild cases, you might not notice any pain at all and only spot the white coating during brushing.
Common Causes and Risk Factors
Candida lives harmlessly in the mouths of most people. Problems start when something disrupts the microbial balance or weakens your immune defenses enough for the fungus to grow unchecked. Several situations make that more likely:
- Antibiotics. They kill bacteria that normally keep Candida in check, giving the yeast room to expand.
- Inhaled corticosteroids. Steroid inhalers used for asthma or COPD deposit medication directly on oral tissues, promoting fungal growth. Rinsing your mouth with water after each use significantly lowers this risk.
- Oral steroids or immunosuppressants. Medications like prednisone or drugs taken after an organ transplant suppress the immune response that would normally contain Candida.
- Uncontrolled diabetes. When blood sugar runs high, your saliva contains more sugar than usual, which feeds Candida directly.
- Weakened immunity. HIV/AIDS, cancer treatment, and chemotherapy all reduce the body’s ability to fight fungal overgrowth.
- Ill-fitting dentures. Dentures that don’t sit properly can irritate tissue and create warm, moist pockets where yeast thrives.
- Very young or old age. Babies have immature immune systems, and older adults often have declining immunity, putting both groups at higher risk.
Smoking and heavy alcohol use also raise your chances. Dry mouth, whether from medication side effects or a medical condition, removes saliva’s natural antifungal protection and creates another opening for Candida.
How It’s Diagnosed
In most cases, a doctor or dentist can diagnose thrush simply by looking inside your mouth. The white patches are distinctive enough that lab tests usually aren’t necessary. If there’s any doubt, or if the infection keeps coming back, a provider may take a small swab from one of the patches and send it to a lab to be examined under a microscope. This confirms the presence of Candida and can help identify the specific species involved, which matters if the infection isn’t responding to standard treatment.
Treatment Options
Thrush is treated with antifungal medication, and the approach depends on severity. Mild cases typically clear up with a topical antifungal, a liquid suspension or a dissolving lozenge, applied directly inside the mouth four to five times a day for one to two weeks. These work by killing the yeast on contact with the oral lining.
If topical treatment doesn’t resolve the infection, or if thrush keeps recurring, a doctor may prescribe an oral antifungal pill that works throughout the body. This systemic approach is more common in people with weakened immune systems or persistent infections. Most healthy adults with a first episode of thrush find that the infection clears within the one-to-two-week treatment window.
Thrush in Babies and Breastfeeding
Oral thrush is especially common in infants during the first few months of life. A baby with thrush may be fussy during feeding, pull away from the breast or bottle, or have visible white patches inside the mouth that don’t wipe away easily.
The critical detail for breastfeeding families: Candida passes back and forth between a baby’s mouth and the mother’s nipples. Both mother and baby need to be treated at the same time, even if only one of them has visible symptoms. Skipping simultaneous treatment is the most common reason thrush keeps coming back in nursing pairs. Some clinicians describe candidiasis as a “family disease” because of how easily it spreads between household members through close contact.
Breastfeeding can and should continue during treatment. Topical antifungals are typically the first step, applied to the baby’s mouth and the mother’s nipples after each feeding. If topical options don’t work, a doctor may move to an oral antifungal for the mother. For infants, oral systemic antifungals are generally reserved for babies six months and older.
What Happens if Thrush Spreads
In healthy people, oral thrush stays localized and resolves with treatment. In people with significantly weakened immune systems, the infection can spread down the throat into the esophagus. This condition, called esophageal candidiasis, causes pain or difficulty swallowing and a feeling that food is stuck in the chest.
Esophageal involvement rarely causes serious complications, but in severe cases it can lead to internal bleeding, narrowing of the esophagus, malnourishment from difficulty eating, or in rare instances, the infection entering the bloodstream. These severe outcomes are almost exclusively seen in people with advanced immune suppression, not in otherwise healthy individuals with a bout of mouth thrush.
Prevention Strategies
A few practical habits lower your risk of developing thrush or prevent it from coming back:
- Rinse after using an inhaler. If you use a steroid inhaler, swish water around your mouth and spit it out after every dose. This removes residual medication from your oral tissues.
- Brush and floss consistently. Brushing at least twice a day and flossing once a day keeps Candida populations in check.
- Keep dentures clean and well-fitted. Remove dentures at night, clean them daily, and see your dentist if they start feeling loose.
- Limit sugar and yeast-heavy foods. Bread, beer, wine, and sugary foods encourage Candida growth. Cutting back can help, particularly if you’re prone to recurring infections.
- Manage blood sugar. If you have diabetes, keeping glucose levels well controlled reduces the sugar available to Candida in your saliva.
- Avoid smoking. Tobacco use irritates oral tissue and disrupts the microbial balance in your mouth.
Regular dental visits also help, especially if you wear dentures, have diabetes, or take medications that dry out your mouth. Your dentist can catch early signs of thrush before it becomes uncomfortable.