What causes a yeast infection?

Jake Bissaro
Jake Bissaro
Published Mar 27, 2023
White, middle-aged woman looking to the right pensively against a marigold yellow background

Key Points:

  1. You can’t see it, but yeast is pretty much everywhere on our bodies.  When certain types grow unchecked, it can cause a yeast infection. 
  2. Yeast infections have a handful of risk factors—for example, being immunocompromised or taking certain medications—but anyone can get a yeast infection for any reason.
  3. If you’re experiencing symptoms, the right treatment is just a consultation away with Dr. B.

What is a yeast infection?

A yeast infection is a common fungal infection caused by an overgrowth of the Candida fungus that results in symptoms like burning, itching and a thick, white discharge when it affects the vagina.

The Candida family of yeast naturally lives on the skin and in the body. A yeast infection occurs when an imbalance of hormones causes Candida to grow unchecked.

The most common signs of a vaginal yeast infection include:

  • An odorless, white vaginal discharge
  • Pain or soreness around the vagina
  • Redness or swelling of the vulva
  • Vaginal rash
  • Small cuts or cracks in the skin of the vulva
  • Pain or burning during intercourse or urination

These symptoms can be similar to other vaginal conditions—to really know if you have a yeast infection, it’s best to seek a diagnosis from a medical provider.

Yeast infections affect people of all ages, races and genders (it can even affect the male genitalia). We explore the various possible causes, and what to do if you experience the symptoms.

The main cause of a yeast infection

Candida is a family of yeast that occurs naturally in small amounts on the skin and in areas like the throat and vagina. In most cases, Candida is harmless. Yeast infection occurs when the yeast grows rapidly, upsetting the healthy balance of bacteria and yeast in the vagina.

Other infections caused by Candida include:

  • Jock itch
  • Athlete’s foot
  • Diaper rash
  • Invasive candidiasis

Factors that can increase your risk of yeast infection include:

  • Hormonal changes that occur during pregnancy, breastfeeding or menopause
  • Taking birth control pills
  • Having uncontrolled diabetes
  • Using antibiotics that kill “good” bacteria in the vagina
  • Being immunocompromised due to conditions like HIV 
  • Using vaginal sprays and douches 

Yeast infections are extremely common—according to the CDC, 75% of women will experience at least one—and anyone can get them at any time. It’s important to be aware of yeast infection symptoms, regardless of whether or not you fit into a higher-risk category.

Are yeast infections contagious?

It’s uncommon, but there are ways that a yeast infection can be transmitted between two people. Though it isn’t considered a sexually transmitted infection like gonorrhea or chlamydia, yeast infections can be spread through vaginal, oral or anal sex.

Keep in mind that men can get yeast infections, too—most commonly from sex with someone who already has a yeast infection. It’s more prevalent among men who are uncircumcised.

How yeast infections are diagnosed

To properly diagnose a yeast infection, a doctor or medical provider may take the following steps:

  • Ask about your medical history: Your provider may ask about previous vaginal infections or risk factors like diabetes, immunocompromised status or medications like birth control pills and antibiotics.
  • Perform a pelvic exam: To check for signs of infection, your provider may examine your genitals by inserting a speculum into the vagina.
  • Take a sample of vaginal discharge: To determine the best course of treatment, your provider may test a sample of vaginal fluid to identify the type of fungus causing the infection.

Learn about other conditions often mistaken for yeast infections.

Online treatment for yeast infections

Dr. B’s licensed medical providers can help you access convenient treatment for yeast infections and a range of other conditions.


Centers for Disease Control and Prevention. (2013). Vulvovaginal Candidiasis (VVC).

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