Oral Thrush (Oral Candidiasis)

Table of Contents

1. What Oral Thrush Is
2. The Different Forms of Oral Candidiasis
3. Causes and Risk Factors
4. Symptoms
5. How Oral Thrush Is Diagnosed
6. Treatment
7. Prevention and Daily Measures
8. Thrush and Inhaled Steroid Medicines
9. Thrush Under Dentures (Denture Stomatitis)
10. Thrush in Babies
11. Complications
12. Warning Signs and Urgent Signs
13. Key Research Papers
14. Connections
15. Featured Videos

What Oral Thrush Is

Candida is a yeast — a single-celled fungus. In most mouths it is a quiet resident, kept in check by three things working together:

• Saliva, which rinses the mouth and carries natural antimicrobial proteins.
• Bacteria of the normal oral community (the oral microbiome), which compete with the yeast for space and food.
• The immune system, especially the white blood cells and the lining of the mouth itself.

Doctors call thrush an opportunistic infection: the yeast does not invade a healthy, well-defended mouth, but takes the opportunity when one of these defences drops. A review in Current Drug Delivery describes how Candida, normally a harmless resident, can become harmful “in case of imbalance of the oral microbiota, the presence of local predisposing factors and systemic conditions that weaken the immune system.”

When the yeast overgrows, it can change shape. Alongside its round yeast cells it grows long thread-like filaments called hyphae, which can push into the surface layer of the mouth lining. Together with dead cells, food debris and bacteria, this builds the soft white coating that gives thrush its name. Most cases are Candida albicans; other species, such as Candida glabrata and Candida tropicalis, turn up less often and some respond less well to common antifungal medicines.

Thrush is very common. The JAMA review lists it as one of the three most common oral conditions, alongside dry mouth and canker sores. A review in the Postgraduate Medical Journal notes that how often it occurs depends on age and on predisposing factors, and that the outlook is good in the great majority of cases.

The Different Forms of Oral Candidiasis

“Thrush” strictly means the white form, but Candida can cause several different-looking problems in and around the mouth. A review in Clinics in Dermatology sorts them into two broad groups — white and red (erythematous) candidiasis — each with several subtypes. A review in Head and Neck Pathology covers pseudomembranous, acute and chronic candidiasis, median rhomboid glossitis and angular cheilitis. The main forms are:

• Pseudomembranous candidiasis (classic thrush). Creamy white or yellowish patches, often compared with cottage cheese or milk curds, on the tongue, inner cheeks, palate or throat. They can usually be wiped off with gauze, leaving a red, sometimes slightly bleeding surface underneath. This is the form most often seen in babies, in people using inhaled steroids and in people with weakened immunity.
• Erythematous (atrophic) candidiasis. Red, raw-looking, often burning patches with no white coating. It commonly appears on the palate or the top of the tongue, where the tongue can lose its small bumps (papillae) and look smooth. This form is easy to miss because there is nothing white to see. It often follows a course of antibiotics.
• Denture stomatitis (chronic atrophic candidiasis). Redness and swelling of the gum and palate in the exact outline of a denture. It is covered in its own section below.
• Angular cheilitis. Sore, red cracks at one or both corners of the mouth. Candida is often involved, frequently together with bacteria. The Postgraduate Medical Journal review groups oral candidiasis into three broad categories: acute candidiasis, chronic candidiasis and angular cheilitis.
• Median rhomboid glossitis. A smooth, red, diamond-shaped patch in the middle of the back of the tongue, linked to long-standing Candida infection.
• Chronic hyperplastic candidiasis. A firm white patch, usually inside the cheek near the corner of the mouth, that does not wipe off. It can resemble other white patches of the mouth lining, which is why dentists usually examine it closely and often take a sample.

Causes and Risk Factors

The cause is always the same yeast. What varies is the reason the defences dropped. The Postgraduate Medical Journal review lists the main risk factors as reduced salivary gland function, medicines, dentures, a diet high in refined carbohydrates, the extremes of life (the very young and the very old), smoking, diabetes, Cushing’s syndrome (too much of the stress hormone cortisol), cancers and conditions that weaken the immune system.

Antibiotics

Broad-spectrum antibiotics kill many of the normal mouth bacteria that compete with Candida, leaving room for the yeast to spread. The JAMA review lists antibiotic use among the common risk factors, and the BMJ Clinical Evidence review names broad-spectrum antibiotics among the conditions linked with overt infection.

Steroid medicines

Corticosteroids dampen the immune response. Taken by mouth they raise the risk throughout the body; inhaled for asthma or chronic obstructive pulmonary disease (COPD), they also leave steroid deposits directly on the lining of the mouth and throat. The inhaled steroid section gives the numbers.

Dry mouth

Saliva is one of the mouth’s main defences against yeast. The JAMA review reported that people with salivary gland hypofunction (an actual drop in saliva production) had higher odds of oral candidiasis (odds ratio 3.02), and that dry mouth was associated with an 11.5% higher risk of oral candidiasis in a pooled analysis of 6 observational studies. Common causes of dry mouth are medicines, head and neck radiation and Sjögren’s syndrome — see Dry Mouth (Xerostomia).

Dentures

Denture plastic is slightly porous, and the space between a denture and the palate is warm, moist and shielded from saliva. Yeast sticks to the denture surface and builds a protective film there. Dentures worn around the clock, especially overnight, are the strongest denture-related risk. See Thrush Under Dentures.

Weakened immunity

Human immunodeficiency virus (HIV) infection is the textbook example. A review in AIDS Research and Human Retroviruses described oropharyngeal candidiasis (thrush of the mouth and throat) as the most common opportunistic infection in people with HIV, becoming more frequent and more severe as immunity declines. The JAMA review gives a prevalence of 35% among people with HIV. Chemotherapy, radiation treatment, organ-transplant medicines and blood cancers raise the risk in the same way.

Diabetes

Poorly controlled blood sugar feeds the yeast and weakens the white blood cells that fight it. The BMJ Clinical Evidence review lists diabetes among the conditions associated with overt infection. Thrush that keeps coming back without an obvious cause is one of the signs that sometimes leads to a diagnosis of diabetes or HIV.

Smoking

Smoking appears on the Postgraduate Medical Journal list of risk factors, and stopping smoking is one of the measures a narrative review of denture stomatitis lists in its management.

Other conditions of the mouth lining

The JAMA review notes that oral mucosal disorders such as oral lichen planus (a long-term inflammatory condition of the mouth lining) are associated with thrush — partly because both the condition and its steroid treatment lower local defences. Deficiencies of iron, folate or vitamin B12, which thin and inflame the mouth lining, are also commonly described as predisposing factors.

Symptoms

Some people with thrush notice almost nothing; others find eating painful. The JAMA review lists oral burning and dysgeusia (a changed or unpleasant taste) as common symptoms. Typical signs and symptoms are:

• Creamy white patches on the tongue, inner cheeks, gums, palate or tonsils that wipe off and leave red, sore spots underneath.
• Redness and soreness, sometimes without any white coating, often on the palate or tongue.
• A burning or raw feeling in the mouth, worse with spicy or acidic food.
• A cottony feeling in the mouth.
• Loss of taste or a bad taste.
• Cracking and redness at the corners of the mouth.
• Soreness under a denture; the palate under the denture is red, while the rest of the mouth looks normal. Denture stomatitis is often painless and found only on examination.
• Pain on swallowing or a feeling of food sticking — a sign that the infection may have spread down into the oesophagus (the food pipe). See Complications.

In babies, the signs are white patches inside the mouth, sometimes fussiness or reluctance to feed. A breastfeeding mother may notice sore, cracked or burning nipples.

How Oral Thrush Is Diagnosed

Most thrush is diagnosed by looking. The Postgraduate Medical Journal review describes management as taking a history, an examination and antifungal treatment, with only a few cases needing samples for laboratory analysis.

In practice, a dentist, doctor or nurse:

1. Looks at the patches. White patches that wipe off to leave a red base are characteristic of pseudomembranous thrush.
2. Asks about triggers — recent antibiotics, inhalers, steroid tablets, dentures and how long they are worn, diabetes, dry mouth, smoking, recent cancer treatment.
3. Takes a sample when the picture is unclear or the thrush does not respond to treatment. A scraping can be looked at under a microscope for yeast cells and hyphae, or grown in the laboratory (a culture) to identify the species and test which antifungal medicines work against it.
4. Takes a biopsy (a small piece of tissue) of a white patch that does not wipe off, to tell chronic hyperplastic candidiasis apart from other white lesions such as leukoplakia, which can be precancerous. See Oral Cancer.

Not every white patch is thrush. A study of 32 healthy infants in Finland, published in Clinical and Experimental Dental Research, found that Candida albicans was not found in any of the four babies diagnosed with thrush by appearance; the cause of their white patches remained unclear. Milk residue on a baby’s tongue, a coated tongue in adults, lichen planus and leukoplakia can all look similar.

When swallowing is painful, doctors look for thrush in the oesophagus. A review in the Canadian Journal of Gastroenterology and Hepatology describes endoscopy (a camera passed down the throat) as the best way to diagnose it: white plaques stick to the lining and cannot be washed off with water, and a biopsy or brushing confirms the diagnosis.

Treatment

The JAMA review summarises treatment as addressing risk factors plus topical and/or systemic antifungal medicines. The Clinics in Dermatology review lists appropriate oral hygiene, topical agents and systemic medicines as the three parts of treatment.

Addressing the trigger

The BMJ Clinical Evidence review notes that, in most people, untreated candidiasis persists for months or years unless the associated risk factors are treated or removed. In practice that means steps such as finishing or changing an antibiotic course, rinsing after an inhaler, removing and cleaning dentures at night, controlling blood sugar, or treating dry mouth.

Topical antifungals (applied in the mouth)

These act on the surface of the mouth and are mostly not absorbed into the body, so they cause fewer drug interactions:

• Nystatin — a liquid suspension swished around the mouth and swallowed, or pastilles. Often used for babies and for mild cases.
• Clotrimazole — lozenges (troches) dissolved slowly in the mouth.
• Miconazole — an oral gel, or a tablet that sticks to the gum and releases the drug slowly.

Topical treatment needs the medicine to stay in contact with the infected surface, so it is usually taken several times a day, after meals, and continued for some days after the patches clear.

Systemic antifungals (tablets or liquid absorbed into the body)

Fluconazole is the most widely used. Itraconazole and posaconazole are used for infections that do not respond, and amphotericin B in hospital for severe cases. The BMJ Clinical Evidence review evaluated all of these, along with topical agents, for preventing and treating thrush in adults whose treatment weakens immunity, in infants and children, in people with dentures and in people with HIV. Systemic azole medicines interact with a number of other drugs (including some blood thinners and cholesterol medicines), which is one reason they are often reserved for more severe infection.

The resistance problem

The AIDS Research and Human Retroviruses review reported growing evidence that Candida albicans strains were developing resistance to the azole drugs, particularly fluconazole, and that other Candida species that are naturally less sensitive to azoles were emerging. To limit resistance, its authors argued that topical medicines be used first for uncomplicated thrush, with systemic azoles kept for cases that do not respond to topical treatment or that involve the oesophagus. A 2023 review in Current Drug Delivery likewise points to drug resistance and the rise of non-albicans species as the reasons researchers are studying alternatives.

Alternatives under study

The Current Drug Delivery review describes three lines of research for recurrent or drug-resistant thrush: plant-derived compounds (phytotherapy), probiotics to rebalance the oral microbiome, and antimicrobial photodynamic therapy (a light-activated dye that kills the yeast). It describes these as alternatives or supports to conventional antifungal treatment and states that further studies are needed to establish how well they work compared with conventional drugs. The BMJ Clinical Evidence review included tea tree oil (melaleuca) among the interventions it assessed; see Tea Tree.

Prevention and Daily Measures

Because thrush is opportunistic, prevention is about keeping the mouth’s own defences intact. The measures described in the reviews cited on this page include:

• Mouth rinsing after inhaled steroids, and use of a spacer device with metered-dose inhalers (see below).
• Denture care: daily cleaning of the denture itself, and taking it out overnight.
• Blood-sugar control in people with diabetes.
• Managing dry mouth, including reviewing medicines that reduce saliva.
• Ordinary oral hygiene — brushing the teeth and gently brushing or scraping the tongue.
• Not smoking.
• Fewer antibiotic courses — each course disturbs the mouth’s bacteria, and antibiotic use is a listed risk factor.

The Postgraduate Medical Journal review notes that in certain high-risk groups — for example, people undergoing intensive cancer treatment or with advanced HIV — antifungal medicine given in advance (prophylaxis) reduces the number and severity of infections.

On diet, the same review lists a diet high in refined carbohydrates among the risk factors. A whole-food diet built around vegetables, legumes, whole grains such as brown rice, and fermented foods such as yogurt, kefir, sauerkraut, miso and natto contains little refined sugar; no record cited on this page tested a specific diet against thrush.

Thrush and Inhaled Steroid Medicines

Inhaled corticosteroids are a mainstay of treatment for asthma and COPD. Part of every puff lands in the mouth and throat rather than the lungs, where it locally suppresses immune defences and lets the yeast grow.

The size of the effect is now well measured. A 2026 meta-analysis in BMJ Evidence-Based Medicine pooled 129 trials with 120,900 participants and found that inhaled corticosteroids were associated with a higher risk of oral candidiasis (risk ratio 2.29, meaning a little more than double the risk of people not using them). Mometasone, beclomethasone, budesonide and fluticasone were all associated with increased risk, with the highest increase for mometasone (4.3%); ciclesonide consistently showed lower risk, reducing oral candidiasis by up to 4.5% compared with the other inhaled steroids.

A Dutch prescription study in Drug Safety of 52,279 new users of inhaled steroids found that prescriptions for thrush medicine were nearly twice as common after starting the inhaler as before (sequence ratio 1.94). The excess was highest in the first 3 months (sequence ratio 2.72) and was still present at 9–12 months (1.47). Higher daily doses and the additional use of steroid tablets predicted thrush.

A 2025 narrative review in Healthcare names high doses, poor oral hygiene and incorrect inhaler technique as key risk factors, and describes prevention as resting on proper inhaler technique and oral hygiene, plus spacers (a tube that holds the puff so less of it settles in the mouth), rinsing the mouth after inhalation and proper denture care.

Thrush from an inhaler is a local side effect; it does not mean the inhaler is harming the lungs. For asthma and COPD, see Asthma and COPD.

Thrush Under Dentures (Denture Stomatitis)

Denture stomatitis is redness and inflammation of the mouth lining covered by a denture, most often the palate under an upper denture. A 2023 narrative review in the International Journal of Environmental Research and Public Health describes it as the most common oral inflammatory lesion in denture wearers, affecting between 17% and 75% of people who wear dentures, with a slight predominance in older women. It is often painless, so many people do not know they have it.

Why it happens

The same review identifies the leading cause as a Candida albicans biofilm (a sticky film of microbes) on the denture, encouraged by poor oral and denture hygiene, long-term denture wear, ill-fitting dentures and the porosity of the acrylic plastic. An interdisciplinary review in the Journal of Prosthodontics names full-time and especially night-time denture wear as a primary cause.

How it is managed

The International Journal of Environmental Research and Public Health review lists oral and denture hygiene, adjusting or remaking poorly fitting dentures, stopping smoking, not wearing the denture overnight, and topical or systemic antifungal medicines as the mainstay of management. A review of the epidemiology of denture stomatitis in the Journal of Prosthodontics explains why the denture itself matters most: antifungal medicines can clear the infection and relieve symptoms, but unless the denture is decontaminated and kept clean, stomatitis returns when the antifungal is stopped, because the yeast survives on the denture. The interdisciplinary review similarly states that antifungal medicines offer limited benefit beyond short-term use because of antifungal resistance, and that long-term success depends on daily cleaning and disinfection of the denture and removing it every night.

Denture stomatitis is more than a local nuisance in frail people. The interdisciplinary review links it with aspiration pneumonia (lung infection from inhaling mouth contents) and associated deaths, and states that treating denture stomatitis in frail, older, medically compromised and nursing-home populations lowers the risk of aspiration pneumonia and related mortality.

Thrush in Babies

Thrush is common in the first weeks and months of life, when the immune system and the mouth’s bacterial community are still developing. Babies can pick up Candida during birth or from the mother’s skin.

• It often clears on its own. The BMJ Clinical Evidence review states that in newborns, thrush of the mouth and throat usually clears spontaneously within 3 to 8 weeks.
• Maternal antibiotics raise the risk. A 2025 study in Breastfeeding Medicine of 82 breastfed infants found Candida albicans growth in 57.5% of babies whose mothers were taking antibiotics, compared with 28.57% of babies whose mothers were not (odds ratio 3.332). Maternal antibiotic use for more than 1 week was associated with oral thrush in the infants.
• Home remedies have been tested. The Finnish infant study looked at the routine practice there of treating white patches with acidic liquids such as lingonberry or lemon juice or soda water. Three of four parents reported the patches were still present after 2 weeks, and the authors concluded that treating them with acidic liquids is not efficient.

When babies are treated, doctors commonly use nystatin suspension or miconazole gel. Mother and baby can pass the yeast back and forth during breastfeeding, so when thrush keeps returning, the mother’s nipples are often treated at the same time.

Thrush that keeps coming back in an older baby or child, or that does not respond to treatment, is less common and can point to an underlying immune or hormonal condition, which is why recurrent cases are usually investigated further.

Complications

Thrush in a healthy person is uncomfortable but rarely dangerous; the Postgraduate Medical Journal review describes the prognosis as good in the great majority of cases. Complications arise mainly in people with weakened immunity or frailty:

• Oesophageal candidiasis. The infection spreads down the food pipe. The Canadian Journal of Gastroenterology and Hepatology review calls it the most common type of infectious oesophagitis, notes that it often occurs together with oral thrush, and lists painful swallowing, difficulty swallowing and pain behind the breastbone as the complaints. Those most at risk are people with HIV or AIDS, leukaemia or diabetes, and people receiving corticosteroids, radiation or chemotherapy. It is treated with antifungal medicine taken by mouth.
• Rare severe complications. The same review lists necrotising oesophageal candidiasis, fistula (an abnormal channel between organs) and sepsis (a body-wide reaction to infection) as uncommon complications, while describing the overall prognosis as good.
• Spread into the bloodstream. In people with very weak immunity — for example after chemotherapy or in intensive care — Candida can enter the blood and spread to organs. This is uncommon and is treated in hospital.
• Aspiration pneumonia in frail denture wearers, as described in the denture section.
• Eating and nutrition. Burning, pain and taste changes can make eating unpleasant, which matters most for older people and people already losing weight from illness.
• Recurrence and resistance. Repeated courses of azole medicines can select for resistant yeast.

Warning Signs and Urgent Signs

Signs that point to thrush

• White patches in the mouth that wipe off and leave red, sore spots.
• Red, burning patches on the palate or tongue, especially after antibiotics.
• A red palate in the shape of a denture.
• Cracked, sore corners of the mouth.
• Changed taste or a cottony feeling in the mouth while using a steroid inhaler.

Signs that suggest an underlying problem

• Thrush with no obvious trigger in an adult who is not using antibiotics, inhalers or dentures. Undiagnosed diabetes and HIV infection are among the conditions that first show up this way.
• Thrush that keeps returning after treatment, or that does not respond to treatment, which can mean a resistant yeast, a non-albicans species or an untreated trigger.
• A white patch that does not wipe off and stays for more than two to three weeks. Persistent white or red patches of the mouth lining are among the signs examined for oral cancer; see Oral Cancer.

Signs that are urgent

• Pain on swallowing, food sticking, or pain behind the breastbone alongside mouth thrush are the symptoms of oesophageal candidiasis, particularly in a person with HIV, cancer treatment, diabetes or steroid use.
• Fever, chills or feeling very unwell with thrush in a person with a weakened immune system (for example during chemotherapy) can mean the infection has spread beyond the mouth, which can be life-threatening.
• A baby who is not feeding, has fewer wet nappies than usual, or seems unusually sleepy is at risk of dehydration, whatever the cause.

Key Research Papers

1. Stoopler ET, Villa A, Bindakhil M, Díaz DLO, Sollecito TP. Common Oral Conditions: A Review. JAMA. 2024;331(12):1045-1054. PubMed PMID: 38530258
2. Millsop JW, Fazel N. Oral candidiasis. Clin Dermatol. 2016;34(4):487-94. PubMed PMID: 27343964
3. Akpan A, Morgan R. Oral candidiasis. Postgrad Med J. 2002;78(922):455-9. PubMed PMID: 12185216
4. Hellstein JW, Marek CL. Candidiasis: Red and White Manifestations in the Oral Cavity. Head Neck Pathol. 2019;13(1):25-32. PubMed PMID: 30693459
5. Pankhurst CL. Candidiasis (oropharyngeal). BMJ Clin Evid. 2013;2013:1304. PubMed PMID: 24209593
6. Contaldo M, Di Stasio D, Romano A, Fiori F, Della Vella F, Rupe C, et al. Oral Candidiasis and Novel Therapeutic Strategies: Antifungals, Phytotherapy, Probiotics, and Photodynamic Therapy. Curr Drug Deliv. 2023;20(5):441-456. PubMed PMID: 35440307
7. Powderly WG, Mayer KH, Perfect JR. Diagnosis and treatment of oropharyngeal candidiasis in patients infected with HIV: a critical reassessment. AIDS Res Hum Retroviruses. 1999;15(16):1405-12. PubMed PMID: 10555102
8. Mohamed AA, Lu XL, Mounmin FA. Diagnosis and Treatment of Esophageal Candidiasis: Current Updates. Can J Gastroenterol Hepatol. 2019;2019:3585136. PubMed PMID: 31772927
9. Pu X, Zhang Y, Peng L, Huang Y, Jiang X, Wang M, et al. Adverse events of inhaled corticosteroids in adult patients with asthma or chronic obstructive pulmonary disease: pairwise, network and dose-response meta-analyses. BMJ Evid Based Med. 2026;31(1):23-35. PubMed PMID: 41241409
10. van Boven JF, de Jong-van den Berg LT, Vegter S. Inhaled corticosteroids and the occurrence of oral candidiasis: a prescription sequence symmetry analysis. Drug Saf. 2013;36(4):231-6. PubMed PMID: 23516006
11. Arzayus-Patiño L, Benavides-Córdoba V. Non-Pharmacological Interventions to Prevent Oropharyngeal Candidiasis in Patients Using Inhaled Corticosteroids: A Narrative Review. Healthcare (Basel). 2025;13(14). PubMed PMID: 40724743
12. Abuhajar E, Ali K, Zulfiqar G, Al Ansari K, Raja HZ, Bishti S, et al. Management of Chronic Atrophic Candidiasis (Denture Stomatitis)-A Narrative Review. Int J Environ Res Public Health. 2023;20(4). PubMed PMID: 36833718
13. McReynolds DE, Moorthy A, Moneley JO, Jabra-Rizk MA, Sultan AS. Denture stomatitis-An interdisciplinary clinical review. J Prosthodont. 2023;32(7):560-570. PubMed PMID: 36988151
14. Gendreau L, Loewy ZG. Epidemiology and etiology of denture stomatitis. J Prosthodont. 2011;20(4):251-60. PubMed PMID: 21463383
15. Mackawy AMH, Alharbi BF, Almatroudi A, Huq M, Mohammed AH, Wasti AZ, et al. The Impact of Maternal Antibiotic Consumption on the Development of Oral Thrush Infection in Breastfeeding Infants: A Quasi-Experimental Study. Breastfeed Med. 2025;20(8):560-566. PubMed PMID: 40160140
16. Vainionpää A, Tuomi J, Kantola S, Anttonen V. Neonatal thrush of newborns: Oral candidiasis? Clin Exp Dent Res. 2019;5(5):580-582. PubMed PMID: 31687193

PubMed Topic Searches

1. PubMed: oral candidiasis treatment
2. PubMed: denture stomatitis and Candida
3. PubMed: inhaled corticosteroids and oral candidiasis
4. PubMed: oral thrush in newborns
5. PubMed: azole resistance in oropharyngeal Candida

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Connections

• Dentistry & Oral Health
• Dry Mouth (Xerostomia)
• Oral Microbiome
• Canker Sores
• Halitosis (Chronic Bad Breath)
• Oral Cancer
• Periodontitis
• Tooth Decay (Dental Caries)
• Fungal Infections
• Yeast Infections
• Sjögren’s Syndrome
• HIV and AIDS
• Type 2 Diabetes
• Asthma
• COPD
• Vitamin B12 Deficiency: Sore Tongue and Mouth
• Tea Tree

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