Why is thrush common in people with diabetes?

Diabetes nurse educator, Christine Manga, explains why thrush is so common in people living with diabetes.

What is thrush?

Thrush is a common fungal infection that affects both men and women. It is also referred to as yeast infection. It is an overgrowth of the naturally occurring fungus Candida albicans.

Any person with a weakened immune system will be more susceptible to thrush. These conditions include but are not limited to diabetes, iron or vitamin B12 deficiency, HIV and autoimmune hypothyroidism. It was even picked up in studies that people with prediabetes had elevated levels of candida.

Where does thrush occur?

Oral and genital thrush are the most common. However, it can also occur in the armpits, between the fingers, in the groin area and under the breasts. Throat and oesophageal thrush are often found in people suffering from HIV/AIDS.

Causes of thrush

Thrush occurs when there is a disruption of the natural balance of good bacteria allowing an overgrowth of the Candida fungus. There are numerous causes for these imbalances.

  • People with diabetes, especially poorly controlled, high blood glucose levels lower the pH of the saliva, making it more acidic. Candida thrives in a lower pH environment.
  • In people with diabetes, there is a diminished tissue response to injury allowing for colonisation of Candida. Examples of injuries include a toothbrush slipping and cutting the gum, braces that cause ulcers as well as ill-fitting dentures.
  • Poor oral hygiene has been positively linked to an increased risk of developing thrush.
  • Xerostomia (low levels of saliva/dry mouth) can be caused by certain medications, such as antidepressants, dehydration and high blood glucose levels. Smoking may not necessarily cause a dry mouth, but it does exacerbate it as well as irritating the mucosal lining of the mouth.
  • Medications that are known to cause thrush include cortisone, inhaled corticosteroids, antibiotics. This is because these kill the good bacteria rendering them unable to control the fungal growth. Hormonal birth control methods can increase the risk of developing thrush by disturbing the body’s natural hormonal balance.
  • Diets that are high in refined and sugary foods. Candida loves sugar!
  • Pregnancy, due to the changes in the hormones.
  • Antibacterial soaps wash away the naturally occurring good bacteria, once again allowing for the overgrowth of fungus. This would be pertinent to genital thrush
  • Overuse of antibacterial mouthwashes.


Oral thrush

  • It usually presents as creamy white patches on the inner cheeks, tongue and gums. It can also be found on the palate.
  • Soreness or a burning sensation.
  • A cotton-like sensation in the mouth.
  • A bad taste in the mouth.
  • Loss of taste.
  • Angular stomatitis – cracks in the corners of the mouth.
  • Possible difficulty in eating and swallowing.

Genital thrush


  • A whitish grey clumpy discharge resembling cottage cheese under the foreskin.
  • Redness or red patches on the head of the penis (glans) and under the foreskin.
  • Difficulty pulling back the foreskin (phimosis).
  • Pain during sex.
  • An unpleasant odour may be present but not always.
  • Can cause burning when passing urine.


  • Vaginal itching.
  • Swelling of the vulva (external part of vagina).
  • Soreness and redness.
  • Pain when passing urine.
  • Whitish grey cottage cheese-like discharge.
  • Pain during sex.


Thrush can be self-diagnosed by looking for the symptoms. You could also visit your doctor who would usually be able to identify it just by having a look. If there is uncertainty, a painless swab of the area can be taken and sent to the laboratory for investigation. If you experience more than four episodes a year, it is advised to visit your doctor.


Treatment is simple. Thrush can clear up on its own. With treatment, it can clear up within three days.

  • An antifungal tablet taken orally and/or cream will be prescribed for both men and women for genital thrush. Women also have the option of a pessary, a soft gel capsule inserted into the vagina.
  • Antifungal tablets, lozenges, oral gels or oral suspensions are used for oral thrush.
  • Natural remedies include eating plain yoghurt or using it as a cream on the affected area. Yoghurt contains naturally good bacteria.
  • Salt water or baking powder baths. Salt is an antiseptic and has soothing properties. Baking soda has been found to be antifungal.
  • Gentian violet can be applied to the affected area in the mouth.
  • In complicated cases, thrush may cause severe damage to the mucosal lining, causing a secondary bacterial infection, possibly needing antibiotic treatment.


  • Good blood glucose control is paramount.
  • Maintaining good hydration.
  • Proper, regular dental care including flossing and brushing teeth. Be careful about the mouthwash that you use.
  • Maintain good hygiene.
  • Avoid antibacterial soaps. Our bodies need the good bacteria. Do not use a loofah, exfoliator or rough sponge on the genitals, this will cause microscopic tears to the mucosa.
  • Try to follow a diet with a lot of whole foods with a low sugar content.
  • Taking probiotics may reduce the risk of thrush infections.
  • Rinse your mouth thoroughly with water after taking and inhaled corticosteroid.
  • Women should wipe from front to back after urinating.
  • Wear cotton underwear.
  • Wear loose fitting clothing.

Although many people with diabetes do suffer from thrush, it is also a very common symptom of diabetes. Many people are tested and diagnosed with diabetes due to recurrent thrush episodes.

Christine Manga (Post Grad Dip Diabetes and Msc Diabetes) is a professional nurse and a diabetes nurse educator. She has worked with Dr Angela Murphy at CDE Centre, Sunward Park since 2012.


Christine Manga (Post Grad Dip Diabetes and Msc Diabetes) is a professional nurse and a diabetes nurse educator. She has worked with Dr Angela Murphy at CDE Centre, Sunward Park since 2012.

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