Is oral thrush contagious?

In adults it is generally not passed to others. In babies it can transfer between the baby’s mouth and the mother’s nipples during breastfeeding, so both may need treatment.

Can I treat oral thrush myself?

Mild cases may be helped by a pharmacy antifungal and good oral and denture hygiene, but see a GP or dentist if it is painful, spreading, not improving, or keeps coming back.

Does having thrush mean something is wrong with my immune system?

Not usually — it is often triggered by dentures, inhalers, antibiotics or dry mouth. But recurrent or unexplained thrush in an adult can occasionally point to an underlying issue such as diabetes, so it is worth checking.

How can I stop thrush coming back?

Rinse your mouth after using a steroid inhaler, clean dentures daily and leave them out overnight, keep good oral hygiene, do not smoke, and manage any underlying condition such as diabetes.

Will thrush go away on its own?

It may, but treatment usually clears it faster and more reliably. Persistent or worsening thrush should be assessed rather than left.

Oral Thrush in Singapore: White Patches, Causes, Care

Written & reviewed by the BestDoctors.sg editorial team · Last updated 24 Aug 2026 · General information, not medical advice

Oral thrush (oral candidiasis) is a fungal infection of the mouth caused by an overgrowth of Candida yeast, which normally lives harmlessly in the mouth. It typically shows as creamy-white, slightly raised patches on the tongue, inner cheeks, palate or gums that can be wiped off to leave a red, sometimes bleeding area. It is common in babies and usually easily treated, and in adults it is often triggered by dentures, inhalers, antibiotics or dry mouth — though recurrent or unexplained thrush can point to an underlying condition worth checking.

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In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.

Thrush that is extensive, very painful or makes swallowing difficult, or thrush in someone with a weakened immune system, needs prompt medical review; and any white or red patch that does not wipe off or heal in about 2–3 weeks should be checked.

What causes it

Thrush develops when the natural balance in the mouth is disturbed and the yeast multiplies. Risk factors include the extremes of age (newborns and older adults); denture wearing, especially with poorly fitting dentures or ones not removed overnight; inhaled corticosteroids for asthma or COPD, particularly without rinsing the mouth afterwards; diabetes, especially when poorly controlled; dry mouth from medicines, conditions or radiotherapy; recent or prolonged antibiotics; and a weakened immune system from HIV, cancer treatment, transplant or immunosuppressant medicines. Nutritional deficiency, an underactive thyroid, smoking and poor oral hygiene are also associated.

Symptoms

The usual signs are white or creamy patches that may wipe off to leave red, raw areas, along with redness, soreness or a burning feeling in the mouth, loss of taste or an unpleasant cotton-wool sensation, and cracked, red corners of the mouth. Soreness can make eating and drinking uncomfortable. In babies, there are white patches that do not wipe away easily, and fussiness or reluctance to feed.

Red flags

Seek prompt care if thrush is extensive or very painful, or makes swallowing difficult or painful, which can signal spread down the throat or food-pipe; if it occurs in someone who is immunocompromised; or if it keeps returning or will not clear with treatment. Thrush alongside unexplained weight loss, persistent tiredness or excessive thirst warrants checking for an underlying cause such as diabetes. Importantly, a white or red patch that does not wipe off, does not heal, or is firm or thickened should not be assumed to be thrush — it needs assessment to exclude other conditions, including precancerous lesions and oral cancer.

How it is diagnosed and treated

Thrush is usually diagnosed by a clinical examination by a GP or dentist, with a swab or gentle scraping sent to the lab if the diagnosis is unclear or the infection is persistent. Blood tests may be advised to look for associated conditions such as diabetes, iron or vitamin B12 deficiency, or thyroid problems, especially with recurrent thrush. Treatment is with antifungal medicine — topical gels, rinses or lozenges for milder cases, or antifungal tablets for more extensive infection — taken as the prescriber directs. Equally important is treating the underlying cause: improving diabetes control, reviewing contributing medicines, correcting nutritional deficiencies and addressing dry mouth. Denture-related thrush usually needs the denture treated as well as the mouth. Most cases in otherwise healthy people clear within a couple of weeks of starting treatment; in infants, an antifungal gel or drops are used, and if breastfeeding, the mother’s nipples may need treating too, to stop it passing back and forth.

Preventing thrush

A few habits markedly reduce the chance of thrush returning. If you use a steroid inhaler, rinse your mouth with water and spit it out after each use, and use a spacer if one is prescribed. Denture wearers should remove dentures overnight, clean them daily, soak them as advised and have the fit checked, since an unclean or ill-fitting denture is a common reservoir. Keeping blood glucose well controlled if you have diabetes, staying well hydrated and managing dry mouth, not smoking, and maintaining good general oral hygiene with regular brushing and dental check-ups all help. Because recurrent adult thrush can be the first clue to an undiagnosed condition, it is worth seeing a doctor rather than simply re-treating it each time. If you wear dentures, ask your dentist to review the fit and advise on a daily cleaning and overnight soaking routine, since a denture is one of the most common places for the yeast to persist; and if you take long-term medicines that dry the mouth or lower immunity, mention this at reviews, as the plan can sometimes be adjusted. Small, consistent habits keep thrush away far more reliably than repeated courses of treatment. A dentist or pharmacist can also recommend the right products for your situation if you are prone to recurrences.

When to see a doctor or dentist

See a doctor or dentist for white or red patches, mouth soreness or a burning mouth that does not settle, for thrush that is painful, affecting swallowing or recurring, or if you have a condition that raises the risk. Babies with suspected thrush or feeding problems should be seen, and any mouth patch, lump or ulcer that has not healed in about 2–3 weeks should be checked.

Related dental & oral-health topics

Sources

NHS — Oral thrush (mouth thrush): nhs.uk
Cleveland Clinic — Thrush (oral candidiasis): clevelandclinic.org
Mayo Clinic — Oral thrush: mayoclinic.org
National Dental Centre Singapore — Oral Medicine Unit: ndcs.com.sg

General information only. This guide is general information about an oral-health topic and is not a diagnosis or personalised dental advice. See a dentist or doctor for assessment and treatment. Any mouth ulcer, lump, or white or red patch that has not healed in about 2–3 weeks should be checked to exclude oral cancer. A spreading dental infection — facial swelling with fever, difficulty swallowing, or difficulty opening the mouth — needs urgent dental or medical care; call 995 if swelling affects breathing or swallowing.

Oral Thrush in Singapore: Causes & Treatment