A vaginal yeast infection is caused by the fungus candida. Candida is a microorganism that's normally present in your vagina, along with bacteria. Your vagina naturally contains a balanced mix of yeast and bacteria. Lactobacillus bacteria produce acid, which discourages overgrowth of yeast in the vagina. But disruption of the healthy balance can result in an overgrowth of yeast. Too much yeast in your vagina can lead to vaginal itching, burning, and other classic signs and symptoms of a yeast infection.

Overgrowth of yeast can result from:

  • Antibiotic use, which leads to a decrease in the amount of lactobacillus bacteria in your vagina and a change in your vaginal pH that allows yeast to overgrow
  • Pregnancy
  • Uncontrolled diabetes
  • Impaired immune system
  • Anything that changes the type and amount of bacteria normally present in the vagina, such as douching or irritation from inadequate vaginal lubrication

Most often, yeast infection results from a type of candida fungus known as Candida albicans. Sometimes, however, a different type of candida fungus might be the cause of symptoms. Candida albicans responds well to typical treatments for yeast infections. Other types of candida, however, sometimes respond poorly to conventional therapies and may require more aggressive treatment.

A yeast infection can be sexually transmitted, especially through oral-genital sexual contact. However, yeast infection isn't considered a sexually transmitted infection because it happens in women who aren't sexually active and the candida fungus is naturally present in the vagina.

Nov. 01, 2012