Oral thrush appears as creamy white patches on the tongue, inner cheeks, and sometimes the roof of the mouth, gums, or tonsils. The patches are slightly raised and have a texture often compared to cottage cheese. One defining feature separates thrush from other white mouth lesions: the patches can be scraped or wiped off, revealing a red, raw surface underneath that may bleed slightly.
What Oral Thrush Looks Like Up Close
The most recognizable sign is those white or yellowish-white patches scattered across soft tissue inside the mouth. They can be small spots or larger plaques that merge together. The tongue is the most common site, but the inner cheeks are a close second. Less often, patches appear on the gums, tonsils, or the soft palate at the back of the roof of your mouth.
Beyond the white patches, thrush changes how your mouth looks and feels in other ways. The tissue surrounding the patches is often red and inflamed. The corners of your mouth may crack and turn red, a related condition sometimes called angular cheilitis. In more advanced cases, the redness and swelling spread, and the white coating can cover large areas of the tongue or cheeks.
Not every case looks dramatic. Early thrush might show just a few small white dots on the inner cheek or a thin white film on the tongue that you notice one morning. It can be easy to mistake for milk residue or a coating from dehydration, but thrush patches are more defined and don’t disappear with drinking water or brushing.
How It Feels
The visual signs are usually what people notice first, but thrush comes with distinct sensations too. A cottony, dry feeling in the mouth is common even when you’re well hydrated. Many people experience burning or soreness, especially when eating acidic, spicy, or hot foods. In more severe cases, the pain can make swallowing difficult.
Some people also notice a change in taste, describing foods as muted or slightly metallic. If you scrape or accidentally disturb the patches while eating or brushing your teeth, you may see slight bleeding from the exposed tissue underneath.
How to Tell It Apart From Other White Patches
Several other conditions cause white patches inside the mouth, and they can look similar at first glance. The scrape test is the simplest way to differentiate thrush at home.
- Oral thrush: White patches wipe or scrape off, leaving a red, sometimes bleeding surface. The patches have a soft, slightly raised texture.
- Leukoplakia: White plaques with sharply defined borders that cannot be scraped off. These are thicker, firmer patches that are stuck to the tissue. Leukoplakia requires medical evaluation because it carries a small risk of precancerous changes.
- Oral lichen planus: Appears as a lacy network of fine white lines (called Wickham striae) on a red base, most often on the inner cheeks. The pattern looks more like a web or fern than the chunky, cottage-cheese patches of thrush. It also cannot be wiped away.
If you try gently wiping a patch with a clean, damp cloth and it comes off, thrush is the most likely explanation. If it stays firmly in place, something else is going on and it’s worth getting evaluated.
What Causes It in Adults
Oral thrush is caused by an overgrowth of Candida, a type of yeast that normally lives in small amounts in your mouth without causing problems. When conditions shift in the yeast’s favor, it changes form, growing thread-like filaments that can penetrate the lining of your mouth and trigger the white patches and inflammation.
Several things tip the balance. Antibiotics kill off the bacteria that normally keep Candida in check, which is why thrush often shows up during or after a course of antibiotics. Inhaled corticosteroids for asthma or COPD deposit medication directly onto the mouth and throat tissue, suppressing the local immune response and encouraging yeast growth. Diabetes, particularly when blood sugar is poorly controlled, creates a high-sugar environment that fuels Candida’s growth and makes it more aggressive. A high-carbohydrate diet can have a similar, though milder, effect.
Weakened immunity from any cause raises your risk significantly. This includes HIV, cancer treatment, immunosuppressive medications, and even the natural immune decline that comes with aging. Iron deficiency, low vitamin B12, and poor nutrition also make the mouth more vulnerable. Locally, wearing dentures (especially overnight or without proper cleaning) creates a warm, moist environment ideal for yeast.
How It’s Treated
Treatment typically starts with topical antifungal medications that you apply directly inside your mouth. These come as rinses you swish and spit, gels applied to the affected areas, or tablets that dissolve against your gum. Most people use a topical treatment several times a day for about one to two weeks.
If topical treatment doesn’t clear the infection, or if your immune system is compromised, your doctor will likely prescribe an oral antifungal pill taken once daily. This systemic approach is more potent and typically resolves stubborn cases within 10 to 14 days. For the rare cases that resist standard treatment, stronger antifungal options are available.
The general strategy is straightforward: start with local treatment and escalate to systemic medication only if needed.
Preventing Recurrence
If you use an inhaled corticosteroid, two simple habits make a significant difference. Rinse your mouth with water (or a baking soda solution) after every puff. This washes away steroid residue that would otherwise sit on your oral tissue and suppress your local defenses. Using a spacer device with your inhaler also helps by directing more medication into your lungs and less onto your mouth and throat.
If you wear dentures, clean and disinfect them daily and remove them for at least six hours each night. Soaking them in a chlorhexidine solution and then letting them air-dry is effective, since air exposure itself helps eliminate Candida. When using antifungal mouth rinses, take your dentures out first so the medication reaches the tissue underneath.
Managing blood sugar if you have diabetes, replacing nutritional deficiencies like iron or B12, and maintaining basic oral hygiene all reduce the chance of thrush coming back. For people who get recurrent episodes, identifying and addressing the underlying trigger matters more than treating each flare individually.