Oral Thrush (Oral Candidiasis)
Oral thrush, or oral candidiasis, is an infection caused by the overgrowth of the fungus Candida albicans in the lining of the mouth. Normally, Candida exists in the mouth as part of the usual flora. However, under certain conditions, it can proliferate excessively and trigger symptoms.
Oral thrush is characterised by creamy white patches that typically affect the tongue or inner cheeks. It may also extend to the roof of the mouth, gums, tonsils, or even the back of the throat.
While anyone can develop oral thrush, it is particularly common in children and older adults due to reduced immunity. It is also more likely to affect individuals with compromised immune systems, specific medical conditions, or those taking certain medications.
In general, oral thrush is a minor issue for healthy individuals. However, symptoms may be severe and difficult to manage in those with weakened immunity.
By Able Health I Medically reviewed by Dr. Alireza Estedlal
Page last reviewed: February 2024 I Next review due: February 2026
Symptoms
In Children and Adults
At first, symptoms of oral thrush may go unnoticed. Common signs include:
- Creamy white spots on the inner cheeks, tongue, and occasionally on the gums, roof of the mouth, or tonsils.
- Slightly elevated lesions resembling cottage cheese.
- Redness, soreness, or burning, which can be severe, making eating or swallowing difficult.
- Minor bleeding when the lesions are scraped or rubbed.
- Redness or cracks at the corners of the mouth.
- A cottony sensation in the mouth.
- Loss of taste.
- Irritation, redness, and discomfort beneath dentures (denture stomatitis).
In more severe cases, typically associated with cancer or a suppressed immune system (such as in HIV/AIDS), the infection may spread to the oesophagus (the long muscular tube extending from the back of the mouth into the stomach). This condition, known as Candida oesophagitis, can cause swallowing difficulties, pain, or the sensation of food being stuck in the throat.
In Infants and Breastfeeding Mothers
In addition to the distinctive white lesions in the mouth, infants with oral thrush may experience difficulty feeding and become fussy or irritable. The infection can also be transmitted to mothers during breastfeeding, potentially leading to a continuous cycle of infection between the child’s mouth and the mother’s breast.
Mothers with a Candida infection on their breasts may notice:
- Abnormally red, itchy, sensitive, or cracked nipples.
- Shiny or flaky skin on the areola (the dark circular region surrounding the nipple).
- Unusual discomfort during breastfeeding or sore nipples between feeds.
- Sharp pains deep in the breast.
Causes
The immune system typically combats harmful organisms like bacteria, viruses, and fungi while maintaining a balance between "good" and "bad" microbes in the body. However, when these defence mechanisms falter, the Candida fungus can overgrow, leading to an oral thrush infection.
Candida albicans is a common type of Candida fungus. Several factors, such as a weakened immune system, can increase the likelihood of developing oral thrush.
Risk Factors
Your risk of developing oral thrush may increase if any of the following apply:
- Weakened immune system: Oral thrush is more common in infants and older adults due to their decreased immunity. Certain health problems and treatments, including cancer and its therapies, organ transplants requiring immunosuppressive drugs, and HIV/AIDS, can also weaken immunity.
- Diabetes: For people with untreated or poorly managed diabetes, saliva may have increased sugar levels that promote the growth of Candida.
- Vaginal yeast infections: These are often caused by the same fungus responsible for oral thrush and can be transmitted from mother to child.
- Medications: Certain medications, such as inhaled corticosteroids, prednisone, and antibiotics that disrupt the normal microbial balance, can increase the risk of oral thrush.
- Other oral disorders: Wearing dentures, particularly upper dentures, or having conditions that cause dry mouth can increase the risk of oral candidiasis.
Complications
Oral thrush is rarely problematic for healthy children and adults. However, in individuals with weakened immune systems, such as those undergoing cancer treatment or living with HIV/AIDS, oral thrush may be more severe.
If left untreated, this condition can lead to more severe systemic Candida infections. For those with compromised immunity, the infection can spread to the oesophagus and other areas of the body.
Diagnosis
Diagnosis of oral thrush is usually based on the location of the infection and identifying any underlying causes.
If the infection is confined to the mouth, a dentist or physician can diagnose the condition by:
- Examining the mouth for lesions.
- Taking small lesion scrapes for microscopic examination.
- Conducting a physical exam and blood tests to assess any potential underlying health conditions contributing to oral thrush.
If oral thrush is suspected in the oesophagus, the doctor may recommend one or more of the following diagnostic procedures:
- Biopsy: Culturing a tissue sample on a special medium to identify the bacteria or fungi responsible for the symptoms.
- Endoscopic examination: Using an endoscope, a flexible illuminated tube with a camera at the end, to examine the stomach, oesophagus, and duodenum (upper region of the small intestine).
- Physical exam: If necessary, physical examinations and blood tests may be conducted to determine if any underlying health conditions are causing oesophageal thrush.
Treatment
The primary aim of oral thrush treatment is to prevent the fungus from spreading. The suitable approach may vary based on age, overall health, and underlying causes. Addressing these underlying causes can help avoid recurrence.
- Healthy children and adults: Antifungal drugs, available in various forms such as tablets, lozenges, or a liquid that is swished in the mouth and then swallowed, are usually prescribed. If topical treatments are ineffective, systemic medications may be recommended.
- Infants and breastfeeding mothers: If the child has thrush, the infection can be transmitted back and forth between the mother and infant during breastfeeding. A mild antifungal drug for the baby and an antifungal cream for the mother’s breasts may be recommended.
- Adults with compromised immunity: Antifungal medicines are typically prescribed.
Oral thrush can sometimes recur after treatment, especially if underlying causes, such as improperly disinfected dentures or the use of inhaled steroids, are not addressed.
Lifestyle and Home Remedies
The following approaches can be helpful during outbreaks of oral thrush:
- Practising proper oral hygiene: Brush and floss your teeth regularly. Replace your toothbrush frequently until the infection clears. Avoid sharing toothbrushes.
- Disinfecting your dentures: Consult your dentist on the best methods for properly disinfecting your dentures to prevent reinfection.
- Warm salt water rinses: In one cup of warm water, dissolve half a teaspoon of salt. Swish the solution in your mouth and then spit it out. Do not swallow.
- Using nursing pads: Breastfeeding mothers with an infection should use nursing pads to prevent the spread of the fungus to clothing. Opt for pads without a plastic barrier, as plastic can promote the growth of Candida. Wear a clean bra daily. Consult your doctor for recommendations on cleaning your nipples, pacifiers, bottle nipples, and removable breast pump parts if applicable.
Prevention
To minimise the risk of Candida infections, consider the following measures:
- Rinsing your mouth: Always rinse your mouth with water if you use a corticosteroid inhaler or brush your teeth after taking medication.
- Practising good oral hygiene: Brush your teeth twice daily and floss regularly according to your dentist’s recommendations.
- Caring for your dentures: Remove your dentures before sleeping. Ensure they fit properly to avoid irritation. Clean them daily, and ask your dentist for the appropriate cleaning method for your specific dentures.
- Regularly visiting your dentist: This is particularly important if you wear dentures or have diabetes. Consult your dentist on how frequently you should visit.
- Watching your diet: Limit your intake of sugary foods, as these can promote the growth of Candida.
- Managing blood sugar levels: If you have diabetes, keep your blood sugar well-controlled to minimise sugar levels in saliva and prevent Candida
- Promptly addressing vaginal yeast infections.
- Treating dry mouth: Consult your healthcare provider about ways to treat or prevent dry mouth.
A Note from MD.co.uk
Oral thrush is a fungal infection affecting the mouth, throat, and potentially other parts of the body. While it can be painful and inconvenient, it is usually easy to treat with antifungal medications in individuals with healthy immune systems. However, those with weakened immunity may find it more challenging to eradicate thrush. If you notice symptoms of thrush, consult your healthcare provider promptly, as early treatment can help you recover quickly and alleviate discomfort.