Oral thrush is a fungal infection caused by an overgrowth of a yeast called Candida, and it usually shows up as creamy white patches on the tongue, inner cheeks, or roof of the mouth. Small amounts of Candida live harmlessly in almost everyone's mouth. Thrush happens when something tips the balance and lets the yeast multiply. It is common, it is treatable, and in most healthy adults it clears within one to two weeks once the trigger is addressed.
Key takeaways
- Oral thrush appears as creamy white patches that can be wiped off, often leaving a red or slightly raw base underneath.
- It is caused by an overgrowth of Candida, most often Candida albicans, when local or general conditions favour the yeast.
- Dry mouth, dentures, inhaled steroid puffers, recent antibiotics, diabetes, and a weakened immune system are the most common triggers.
- Treatment usually involves an antifungal gel or rinse plus fixing the underlying cause, such as cleaning dentures properly or rinsing after a steroid puffer.
- A white patch that will not wipe away, or one that keeps coming back, should be checked by a dentist or doctor.
What oral thrush looks and feels like
The classic form, called pseudomembranous candidiasis, produces soft white or cream coloured plaques that look a little like cottage cheese or curdled milk. Gently wiping them away often reveals a reddened surface underneath, which is a useful clue that separates thrush from other white patches that stay stuck down. Some people notice a burning or sore feeling, a cottony sensation, or a loss of taste. Not every case is white, though. An erythematous form appears as flat red, tender areas, often on the tongue or palate, and is sometimes called antibiotic sore mouth because it follows a course of antibiotics.
The single rule worth remembering
Thrush is rarely random. It is almost always a sign that something has shifted the balance in your mouth or your general health. That is why treatment works best when you tackle both the infection and its trigger. Clearing the yeast without changing what caused it often means the thrush simply returns.
| Type | How it looks | Common trigger |
|---|---|---|
| Pseudomembranous | Creamy white patches that wipe off | Antibiotics, dry mouth, weakened immunity |
| Erythematous (atrophic) | Flat red, sore areas | Recent antibiotics, denture wear |
| Denture stomatitis | Red, inflamed area under a denture | Continuous denture wear, poor cleaning |
| Angular cheilitis | Cracked, sore corners of the mouth | Candida spread, saliva pooling, low iron or B vitamins |
What causes the overgrowth
Candida takes advantage of local and general changes. Local factors include a dry mouth, which removes saliva's natural cleansing and antifungal effect, and dentures that trap yeast against the gums, particularly when worn overnight or not cleaned well. Inhaled corticosteroid puffers used for asthma leave steroid residue in the mouth that can encourage yeast, which is why rinsing and spitting after each dose matters. General factors include recent broad spectrum antibiotics that clear away competing bacteria, poorly controlled diabetes, pregnancy, older age, and any condition or medication that lowers immune defences. Babies commonly develop thrush because their immune systems are still developing.
Who is more likely to get it
Denture wearers are a large group, with studies suggesting a high proportion of people with removable dentures carry some degree of Candida related inflammation. People using steroid puffers, those on chemotherapy or immune suppressing medicines, and anyone with an ongoing dry mouth are also at higher risk. If you notice repeated episodes, it is worth reviewing whether a medication, an undiagnosed condition such as diabetes, or a denture habit is driving them. A related read is our guide to dry mouth and how to manage it, since saliva is one of the mouth's main defences against yeast.
How oral thrush is treated
Most cases respond to a topical antifungal, such as a nystatin oral drops or a miconazole oral gel applied to the affected areas over one to two weeks. It is important to keep using the medicine for the full course, even after the patches fade, so the yeast does not rebound. One practical caution: miconazole gel can interact with the blood thinner warfarin and increase bleeding risk, so always tell your dentist or pharmacist about your medicines before starting treatment. For denture related thrush, the dentures usually need to be left out as much as possible while healing, cleaned thoroughly each day, and soaked overnight rather than worn. More stubborn or widespread infections, especially in people with weakened immunity, may need an oral tablet prescribed by a doctor.
How to prevent it coming back
Prevention follows the triggers. Rinse your mouth with water after using a steroid puffer. Clean dentures every day and take them out overnight. Keep on top of a dry mouth with sips of water, sugar free gum, and by asking your dentist about saliva substitutes. Manage diabetes well, since high blood sugar feeds yeast. Brush twice a day and clean between your teeth so the whole mouth stays healthy. If you have just finished antibiotics and notice soreness, mention it at your next visit.
General cost guide
Costs vary between clinics and depend on whether a review, a swab, or denture adjustments are needed. The figures below are general market ranges across Australian practices, not a quote.
| Item | General cost guide (AUD) |
|---|---|
| Dental examination and diagnosis | $60 to $250 |
| Antifungal gel or drops (pharmacy) | $10 to $30 |
| Denture clean and assessment | $50 to $150 |
For current new patient offers you can see our current deals page, and we are always happy to provide a written estimate before any treatment.
When to see a dentist or doctor
See someone if the patches do not clear within two weeks of treatment, if they keep returning, if swallowing becomes painful, or if you have a condition that weakens your immune system. A white patch that will not wipe off is a different problem and should always be assessed, as covered in our guides to oral leukoplakia and a white coated tongue. Cracked, sore corners of the mouth may be linked thrush and are explained in our angular cheilitis guide.
Frequently asked questions
Is oral thrush contagious?
In healthy adults it is not usually passed on through everyday contact, since Candida already lives in most mouths. Mothers and babies can pass it back and forth during breastfeeding, so both may need treating at the same time.
Can I get rid of oral thrush without medication?
Mild cases can settle once the trigger is removed, but an antifungal usually clears it faster and more reliably. It is best to have it assessed rather than assume it will resolve, especially if it is spreading.
Why do I keep getting thrush?
Recurrent thrush points to an ongoing trigger such as a steroid puffer without rinsing, a dry mouth, uncontrolled diabetes, or a denture worn overnight. Identifying and fixing that trigger is the key to stopping the cycle.
Does thrush cause bad breath?
It can contribute to an unpleasant taste or mild odour, particularly with denture stomatitis, though bad breath has many causes and is worth assessing separately.
Can children get oral thrush?
Yes, it is common in babies and appears as white patches that do not wipe away easily. If your baby is feeding poorly or you are unsure, see your dentist, doctor, or child health nurse.
If you are noticing white patches, soreness, or a mouth that feels off, the team at Lumi Dental in Melrose Park can assess it and talk you through the options. Read more about our general dental care or view our current offers.
This article is general information only and is not a substitute for personalised advice from a dental or medical professional. If you have concerns about your oral health, please book an appointment for an assessment.
