Oral thrush

Oral thrush, also known as oral or oropharyngeal thrush, is a fungal infection that affects the mouth, tongue and oesophagus. Candida is commonly found in the human body, but does not always cause infections. Infections occur when the fungi grow uncontrollably. Oral thrush is more common in infants and the elderly, but can occur at any age. It is usually treated and cured without difficulty. Here is everything you need to know about oral thrush.

In most cases, oral thrush develops when the immune system is weakened. This is why it is more common among babies and the elderly.
 

What causes oral thrush?

Candida is present in the body in the mouth, the digestive tract, and on the skin, just like many other bacteria and microorganisms. When other conditions, stress, or certain allopathic treatments affect the bacterial flora and cause imbalances, this fungus can lead to oral thrush.

Medicines that can upset the balance of the bacterial flora and cause infections include:

• Corticosteroids;
• Antibiotics;
• Oral contraceptive pills.
   

Risk factors for oral thrush

Candida infection is more likely to develop in people who:

• Have diabetes;
• Smoke;
• Have cancer and, consequently, a weakened immune system;
• Wear ill-fitting dentures that do not fit perfectly, or unsuitable or poorly positioned orthodontic appliances;
• Have poor oral hygiene;
• Suffer from xerostomia (dry mouth) 
• Are experiencing significant hormonal fluctuations, most often caused by pregnancy;
• Have a weakened immune system;

Given that people with braces or dentures are more prone to contracting a fungal infection that can lead to oral thrush, particularly where oral hygiene is inadequate, it is very important to visit the dentist. The dentist is the specialist who can provide information on maintaining good oral health, through adherence to oral hygiene rules, as well as regular visits to the surgery.
 

How is oral thrush transmitted?

Anyone can suffer from oral thrush, from newborns and infants to adults and the elderly with a compromised immune system, although in these cases the symptoms are harder to control. At the same time, thrush affecting the oesophagus is one of the most common infections among people diagnosed with HIV.

Although it is not considered a highly contagious infection, it can be transmitted via saliva. If you come into contact with someone suffering from oral thrush, you should wash your hands frequently and avoid contact with their saliva, as thrush can also be transmitted via contaminated objects.

Oral thrush is caused by one of over 200 species of Candida, most of which are harmless. Candida albicans, Candida tropicalis, Candida krusei, Candida parapsilosis and Candida glabrata are the most common of these species.

Here’s what you can do to prevent the infection:

• Establish a routine for proper oral hygiene. Brush your teeth at least twice a day and use dental floss to remove all food debris. If you are undergoing treatment with corticosteroids, it is important to brush your teeth or rinse your mouth with water or mouthwash after taking them.
• Pay particular attention to the hygiene of your dentures, if you use them, and consult your dentist if they do not fit your jaw perfectly.
• Manage your diabetes if you have this condition and limit your sugar intake, as this can encourage the development of oral thrush.
• Cut down on or give up smoking altogether.
• Have regular dental check-ups, especially if you are undergoing orthodontic treatment.

Oral thrush develops suddenly, with no symptoms to indicate the onset of the infection. A common symptom is a change in saliva and the appearance of lesions on the tongue or the inside of the cheeks. These lesions are whitish and have a creamy texture. They may also appear on the roof of the mouth, on the gums, on the tonsils or on the oesophagus.

Other symptoms of oral thrush include:

• Redness and pain in the mouth or at the corners of the lips;
• Partial loss of taste;
• A dry mouth;
• Mouth pain and bleeding, which can be triggered even whilst brushing your teeth. In more severe cases, these lesions can spread to the oesophagus and cause pain and difficulty swallowing.
• Fever, if the infection spreads to the oesophagus.

Oral thrush can also spread to other parts of the body, such as the lungs, liver or skin. This is more common in people with severely compromised immune systems, who have cancer (including oral cancer), HIV infection or other conditions that weaken the immune system. In the case of oral cancer, which, incidentally, has a survival rate of just 30%, the onset of oral thrush symptoms is all the more common. For an accurate diagnosis of this condition, oral cancer screening procedures are recommended, which can be carried out at DENT ESTET, thanks to LED Dental technology, using the VELscope VX device.

Superficial candidiasis, which affects the mucous membranes and skin, can be treated with medication; however, there are also invasive strains, resistant to antifungal drugs, which can spread to other organs. Therefore, oral candidiasis must be treated as soon as the first signs appear, to prevent it from spreading.
 

How does oral thrush manifest in newborns and infants?

In infants and newborns, oral thrush manifests as white patches or lesions inside the mouth and on the lips, as well as skin rashes. In infants, thrush can be passed on from the mother if she has a fungal infection of the breasts whilst breastfeeding. This is precisely why detecting and treating thrush is important for both babies and mothers. Proper hygiene can prevent it from spreading.

There are several types of oral thrush. Based on their appearance, they are classified as follows:

• Pseudomembranous candidiasis – characterised by the appearance of white patches or a complete coating of a whitish substance, which, upon removal, reveals erythematous lesions or even bleeding of the mucosa.
• Erythematous candidiasis manifests as open lesions and has several subtypes: denture-associated stomatitis, angular stomatitis, median rhomboid glossitis and antibiotic-induced stomatitis.
• Hyperplastic or nodular candidiasis manifests as persistent, whitish, nodular lesions.

Another classification distinguishes between:

• Chronic multifocal oral candidiasis, whose manifestations extend over longer periods 
• Chronic mucocutaneous candidiasis, which usually occurs against a background of a pre-existing infection with another Candida subspecies. 

Depending on the severity of the symptoms, oral candidiasis can be mild, moderate-severe or persistent (acute).

To treat oral thrush effectively, it is important that it is detected and diagnosed correctly and in good time.
 

Diagnosing oral thrush

The doctor can diagnose the infection by examining the mouth and assessing the symptoms. In some cases, a tissue sample may be taken for a biopsy to confirm the diagnosis. If the doctor suspects oesophageal candidiasis, they may take a swab sample from the throat or use endoscopy to confirm the diagnosis. The throat swab will be taken using a sterile cotton swab, which will then be sent for testing in a laboratory. In the case of endoscopy, the doctor will use a thin tube with a camera attached, which they will insert through the mouth to examine the oesophagus. It is also possible to take a tissue sample for further analysis during the endoscopy.
 

Treatment of oral thrush

Oral thrush is a condition which, if not chronic, can be treated relatively easily and within a fairly short time.
 

Treatment for oral thrush

For medical treatment, the dentist may recommend antifungal medicines containing active ingredients such as fluconazole, clotrimazole, itraconazole (usually recommended if the patient does not respond to the treatments listed above) or amphotericin B (usually recommended for the treatment of severe oral thrush).

In most cases, symptoms disappear within a few weeks of starting allopathic treatment, but may return later. In cases of recurrent oral thrush with no known cause, the dentist may recommend that the patient be assessed for other conditions that could contribute to the development of thrush.
 

Natural remedies for oral thrush

In addition to allopathic antifungal treatment, the doctor may also recommend some additional measures to combat oral thrush. Proper oral hygiene plays an important role in preventing the development of such infections. Changing your toothbrush after completing allopathic treatment, brushing your teeth correctly and avoiding brushing areas affected by lesions, and avoiding mouthwashes and sprays unless recommended by your doctor are the first steps you can take to treat thrush.

In addition to these, there are a number of remedies that can help alleviate symptoms. These are usually used for an additional rinse after completing your oral hygiene routine:

• Salt water;
• A solution made from water and baking soda;
• A solution made from water and fresh lemon juice;
• A solution made from water and apple cider vinegar.

Such solutions help to balance the bacterial flora in the mouth. Alongside these, consuming yoghurt, pickles or other foods containing natural probiotics, or taking a probiotic dietary supplement, can support recovery from oral thrush.

It is important to discuss this with your dentist before starting any treatment.

Oral thrush has specific symptoms, which can usually be detected from the very first signs. Depending on the severity of the infection, short-term treatment may be required, or long-term treatment may be necessary for chronic or recurrent infections. Your dentist will guide you towards the best treatment options, depending on the symptoms and your body’s response to antifungal medication. 

Resources:

• Mayo Clinic Staff (n.d.) Oral thrush: Symptoms and causes.
• Healthline. (n.d.). Thrush.
• CDC (Centres for Disease Control and Prevention) – Candidiasis: signs and symptoms
• DermNet NZ. (n.d.). Oral candidiasis.
• Symptoms and treatment for oral thrush, Medically reviewed by Nicole Leigh Aaronson, MD, MBA, CPE, FACS, FAAP — Written by Tim Newman and Adam Rowden — Updated on 7 February 2024, Healthline Media UK Ltd.
• NHS – Oral thrush (mouth thrush)
• Pharmaceutical Journal (n.d.) Oral candidiasis: causes, types and treatment.
• Taylor M, Brizuela M, Raja A. Oral Candidiasis. [Updated 4 July 2023]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; January 2026.