What Causes a Yeast Infection? 7 Causes & What to Do

What causes a yeast infection can depend on many factors. A vaginal yeast infection (vulvovaginal candidiasis) can happen due to an imbalance in the vaginal microbiota that can be caused by stress, a weakened immune system, hormone changes, or the use of antibiotics.

A yeast infection is caused by Candida albicans, which is a common fungus found naturally on the body, primarily in the mouth, gut, vaginal tract, and on the skin. It can live on the body as part of the normal flora without causing any symptoms.

However, an overgrowth of this fungus can lead to signs and symptoms of infection, such as pain and burning with urination, vulvovaginal itching, and pain or discomfort during sex. 

person wearing jeans and a striped T shirt scratching their crotch over their jeans

Main causes

Common causes of an increased risk for yeast infections include:

1. Wearing tight clothes or underwear made from synthetic fabrics

Wearing underwear made from synthetic fabrics and/or tight pants or shorts can increase the risk for a vaginal yeast infection because it creates a hotter, more humid environment that allows fungi to grow and multiply. 

It is important to wear cotton underwear and lightweight, loose-fitting clothing to allow for proper ventilation and to prevent an imbalance of the vaginal microbiota. 

2. Taking antibiotics

Broad spectrum antibiotics are used to treat infections, however in addition to killing off the bacteria causing the infection they also decrease the number of "good bacteria" that are responsible for keeping fungal growth under control.

This creates an imbalance in the vaginal microbiota, allowing Candida albicans to grow unchecked and resulting in infection. 

3. Having uncontrolled diabetes

Uncontrolled diabetes can also increase the risk for a yeast infection due to high levels of sugar circulating in the blood stream, which can encourage the growth of fungi in the vaginal tract.

People with uncontrolled diabetes may suffer from recurrent yeast infections. It is therefore important that people with diabetes are followed closely by an endocrinologist or their primary care provider to develop a treatment plan to keep their diabetes under control.

4. Suffering from stress or anxiety

High levels of stress and anxiety can lead to a weakened immune system that is less capable of defending the body against infection. It is common to experience an imbalance in the microbiota during times of high stress that can increase the risk for infections, including yeast infections.

5. Experiencing hormonal changes

Hormone changes are common during pregnancy and menopause, which can also promote the development of fungi that cause yeast infections.

6. Having an autoimmune disease

Autoimmune diseases are one of the most important risk factors for developing a yeast infection. Conditions like lupus and rheumatoid arthritis, as well as immunosuppressive treatments related to HIV or cancer, can cause a yeast infection to develop.

In the case of a yeast infection, it is important to see a gynecologist or your primary care provider to identify a potential cause and arrange for the most appropriate treatment. 

7. Using oral contraceptives (birth control)

Taking oral contraceptives can increase levels of estrogen in the body, which can enable the growth of Candida albicans and result in a yeast infection.

What to do

In order to prevent a yeast infection, it is important to maintain good hygiene, use cotton underwear, and avoid wearing tight clothing to keep the genital area clean and dry.

In the case of yeast infections related to uncontrolled diabetes, it is important to follow a diabetes treatment plan as advised by your doctor or primary care provider in order to decrease blood sugar levels and prevent infections.

Your healthcare provider may prescribe medications like antifungal ointments, creams, or pills to kill off the excess fungi and relieve symptoms. See yeast infection treatment.