Diabetes and Thrush

Medically Reviewed by Michael Dansinger, MD on April 09, 2022
3 min read

If you have diabetes, a weakened immune system -- your body's defense against germs -- makes it more likely that you'll get infections, including one called thrush.

Thrush is an infection caused by the candida fungus. It's also called candidiasis or a yeast infection. Anyone can get it. But it's more of a problem for people with diabetes.

When you have diabetes, the level of sugar in your blood is too high. If you don't control it, it causes damage over time that makes your body the perfect environment for a yeast infection.

Many kinds of fungus and bacteria live naturally on your skin and inside your body. Normally, you don't even know they're there. There's a balance between them and your immune system that keeps them from causing trouble. But if something tips that balance, the bacteria or fungus can grow out of control and cause an infection.

Diabetes weakens your immune system by making changes to the cells that normally fight germs. That makes it harder for your body to defend and heal itself. As a result, you're more likely to get all kinds of infections, including thrush.

Yeast infections are a particular problem with diabetes because sugar helps candida grow. High levels of sugar in your blood also mean high sugar levels in your sweat, saliva, and urine. That encourages yeast to grow in places like your mouth and genitals, and you can end up with thrush.

It's unusual for a healthy adult to get a yeast infection in their mouth. But when you have diabetes, yeast thrives on the extra sugar in your saliva.

Diabetes can also give you a dry mouth, which helps the yeast take hold. Signs you have oral thrush include:

  • Pain in your mouth and throat
  • White patches on your tongue, inside the cheeks, and on the roof of your mouth
  • Redness or bleeding inside your mouth
  • Bitter taste or loss of taste
  • Cracks in the lips or corners of your mouth

Genital yeast infections are more common in women, but men can get them, too. Most women have one at some point in their lives. For men, it's more likely if you're uncircumcised.

Genital yeast infections have several uncomfortable, telltale signs. In women, they include:

  • Itching and irritation in and around your vagina
  • Pain when you pee or have sex
  • Redness
  • Thick white discharge

Symptoms in men include:

  • Pain around the head of your penis
  • Redness
  • Itching
  • Penile discharge that's white, particularly underneath your foreskin
  • Pain when you pee or have sex
  • Bad smell around your penis

Thrush can take hold in other areas of your body, especially where you have skin folds that trap moisture. That can be under your breasts, in your armpits or groin, or between your fingers and toes. You'll notice an itchy, red rash with tiny blisters and scales.

Yeast can cause toenail fungus and foot sores. It can also cause a urinary tract infection, particularly in people who have to use a catheter.

A very serious kind of yeast infection is called invasive or systemic candidiasis. That's when the infection is in your bloodstream or internal organs. It's a big problem for people in the hospital and can be life-threatening.