Health Tips

Oral thrush, or clinically known as oropharyngeal candidiasis, is a fungal infection in the mouth and throat. In healthy adults, candidiasis in the mouth and throat rarely happens. However, certain groups of peoples are more likely to develop candidiasis for reasons we will discuss below. 

The fungus that causes candidiasis belongs to the group called Candida (hence the name ‘candidiasis’). Candida albicans (C. albicans) accounts for around 80% of infections. 

Signs and Symptoms 

Many people with oropharyngeal candidiasis do not have any symptoms. However, when symptoms do occur, individuals commonly experience a cottony feeling in the mouth, loss of taste, and, in some cases, pain during eating and swallowing. In some cases, the infection can also cause angular cheilitis, which is a condition that causes red, swollen patches in the corners of your mouth where your lips meet and make an angle.

James Heilman, MD, CC BY-SA 3.0 , via Wikimedia Commons

Matthew Ferguson 57, CC BY-SA 3.0 , via Wikimedia Commons

Who are at risk of developing candidiasis in mouth and throat

Oropharyngeal candidiasis is an opportunistic infection, i.e. which is an infection that occurs more often or severely in people with weakened immune systems. 

Candida is commonly found in people’s mouth, throat, gut and vagina. For healthy individuals, candida infection happens rarely because the microbial flora keeps the populations of Candida under controlled.

However, in people with weakened immunity, Candida can overgrow and lead to candidiasis. 

Candidiasis in the esophagus (the tube that connects the throat to the stomach) is called esophageal candidiasis or Candida esophagitis. Esophageal candidiasis is one of the most common infections in people living with HIV/AIDS.

Besides people living with HIV/AIDS, the following group of people have weakened immunity and thus having higher risk of developing candidiasis in mouth and throat:

• People with weakened immunity and wearing dentures

• People with diabetes

• People have dry mouth (called xerostomia)

• People treated with broad-spectrum antibiotics for a long period of time. This is also known as ‘antibiotic sore mouth’. This particular case of candidiasis is called acute atrophic candidiasis, which is associated with a burning sensation in the mouth or on the tongue.

• Asthma patients who use inhaled corticosteroid (e.g. beclomethasone, budesonide,fluticasone). Oral thrush is one of the side effects of using inhaled corticosteroids.

• People who are undergoing cancer chemotherapy or any immunosuppressive therapies (such as after organ transplantation)

While oropharyngeal candidiasis is not life-threatening, it can cause significant discomfort. If it happens to elderly or hospitalised patients, they may experience malnutrition due to difficulty in eating.

Medicines to treat oral thrush

The common treatment for oral thrush is nystatin suspension, which is a medication for fungal infection. Doctors may prescribe nystatin solution to prevent and treat oral thrush.

Image credit: http://drshikinzainal.blogspot.com/2014/09/oral-candidiasis.html

• Shake the bottle well before use, then draw up the correct amount into the measuring dropper provided.

• Swish the suspension throughout or be retained in the mouth for as long as possible before swallowing.

• Avoid eating or drinking anything within an hour after taking the medication

Nystatin is generally safe to use. Some mild side effects of the medication may include nausea, vomiting, stomach upset and diarrhoea. If you develop any severe allergic reactions after taking nystatin suspension, stop taking it and visit a doctor immediately.

If oral thrush is not resolved after nystatin treatment, the doctor may prescribe systemic treatment (‘stronger’ antifungal) such as fluconazole and itraconazole. They can be administered as the form of pills, liquid or injection.

Practise good oral hygiene

Besides taking medications prescribed by the doctor, it’s important that people with high risk of developing candidiasis to practise good oral hygiene:

• Rinsing mouth out after eating, taking medication or using a corticosteroid inhaler

• Good oral hygiene, brushing teeth twice per day

• Going for regular dental check-ups (even if patients do not have any teeth)

For denture wearers:

• Properly cleaning dentures

• Brushing gums with a soft toothbrush

• Removing dentures each night

• Ensuring dentures fit properly and are not too loose

For babies,

• Sterilising dummies regularly and bottles after each use

• If using corticosteroid inhalers, rinsing the mouth with water or cleaning a child’s teeth (if not able to rinse and spit) immediately after using the inhaler.

A word from DOC2US

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Specific references have been linked in its relevant part of the article. 

Cover image credit: CDC

Written by

Ms Joyce Toh