Tongue thrush appears as creamy white, slightly raised patches that look like cottage cheese. The patches stick to the surface and don’t rinse or wipe away easily. When scraped off, the tissue underneath is red, raw, and may bleed slightly.
The Classic Look of Oral Thrush
The most recognizable sign is white patches or spots on the tongue, inner cheeks, or inner lips. These aren’t flat stains. They’re slightly raised from the surface and have an uneven, curd-like texture. The white coating can start as small, scattered spots and merge into larger patches as the infection grows.
A key feature that separates thrush from other white spots in the mouth: the patches can be physically scraped or rubbed off. But doing so reveals irritated, reddened tissue underneath that may bleed. This is actually one of the ways clinicians confirm the diagnosis. Other white oral lesions, like leukoplakia, are firmly attached and cannot be wiped away at all.
Thrush doesn’t always look purely white, though. There are several presentations. The most common (pseudomembranous candidiasis) produces those classic white plaques. But an atrophic form shows up as widespread redness across the mouth’s lining without much white coating. A less common hyperplastic form creates thicker white patches, especially on the sides of the tongue and corners of the mouth, that don’t wipe off as easily.
How It Feels, Not Just How It Looks
Thrush isn’t only visual. You’ll likely notice a cottony feeling in your mouth, as if the texture of your tongue or cheeks has changed. Food may taste different or muted, since the infection can dull your sense of taste. Redness and soreness at the corners of the mouth are common, and the patches themselves can become irritated and painful, especially while eating or brushing your teeth.
In mild cases, there may be little to no discomfort. More developed infections tend to cause burning or soreness, particularly with acidic or spicy foods.
Thrush on a Baby’s Tongue vs. Milk Residue
Parents often wonder whether the white coating on their infant’s tongue is thrush or just leftover milk. The distinction is straightforward. A milk diet commonly causes a white-coated tongue in babies, and that’s completely normal. Milk residue washes away on its own or wipes off easily with a damp cloth.
Thrush sticks. It won’t rinse away or come off with gentle wiping. It also tends to form odd-shaped, irregular patches rather than an even coating. Another clue: if whiteness appears only on the tongue and nowhere else, it’s more likely milk residue. Thrush typically spreads to the inner cheeks and inner lips as well.
Where Thrush Can Spread Beyond the Tongue
Thrush usually starts on the tongue and inner cheeks, but the infection can extend to the roof of the mouth, the gums, the tonsils, and the back of the throat. In more severe or untreated cases, especially in people with weakened immune systems, the fungus can reach the esophagus. When that happens, swallowing becomes painful or difficult, and you may feel like food is getting stuck in your chest.
What Causes It
Thrush is caused by an overgrowth of Candida, a fungus that normally lives in your mouth in small amounts. Your immune system and the balance of other microorganisms usually keep it in check. When something disrupts that balance, Candida multiplies and produces the visible patches.
The most common triggers are medications. Antibiotics kill off bacteria that normally compete with Candida, giving the fungus room to grow. Inhaled corticosteroids, the kind used in asthma inhalers, deposit small amounts of steroid in the mouth and throat that suppress local immune defenses. Chemotherapy and other drugs that weaken the immune system also raise the risk significantly. Conditions that cause dry mouth are another contributor, since saliva plays an important role in keeping Candida populations low.
Conditions That Look Similar
Not every white patch in the mouth is thrush. Two conditions commonly mimic its appearance.
- Leukoplakia produces white plaques that are usually well-defined and painless. The critical difference is that these patches cannot be wiped or scraped off. They’re firmly attached to the tissue. Leukoplakia requires a clinical evaluation because some cases carry a small risk of becoming precancerous.
- Oral lichen planus creates white, lacy, web-like patterns (called Wickham striae) that appear symmetrically on the inner cheeks. The pattern is distinct from thrush’s irregular, curd-like patches. Lichen planus often has no symptoms in its reticular form, though erosive forms can be painful.
The scrape test is the simplest way to tell them apart at home. If a white patch wipes off and leaves red, sore tissue behind, thrush is the most likely explanation.
Treatment and How Long It Takes
Thrush is treated with antifungal medication, typically a liquid suspension that you swish around your mouth and then swallow. The goal is to keep the medication in contact with the affected tissue for as long as possible before swallowing. Treatment usually continues for at least 48 hours after the visible patches and soreness have fully cleared, to prevent the infection from bouncing back.
Most mild cases improve within a week or two of starting treatment. If you use an inhaled corticosteroid for asthma or another condition, rinsing your mouth with water after each use can significantly reduce your risk of developing thrush in the first place. For people with recurring infections, identifying and addressing the underlying trigger, whether it’s a medication, dry mouth, or an immune system issue, is the most effective long-term strategy.