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Yeast Infection

  • A disrupted balance of good bacteria and yeast around the vagina that causes itching and discomfort
  • Symptoms include itchiness, inflammation, and discomfort in the vaginal area
  • Treatments include anti-fungal cream or oral medication, and other options for longer term care
  • Involves gynecology

Yeast Infection


If you are a woman, the odds are high that you’ve had at least one yeast infection. And if you are among the lucky few who haven’t, it’s likely that you will get one someday. It is usually signaled by itchiness, inflammation, and general discomfort in the vaginal area. Though they happen more frequently in women, men can get them, too, in the groin.

For women, a yeast infection occurs when the delicate balance of good bacteria and naturally occurring yeast in and around the vagina is disrupted. The possible causes of infection are numerous. They range from changes in the physical environment, like sitting for too long in a wet bathing suit, to changes in life circumstances, like severe stress or lack of sleep. They are also more common during pregnancy and after a course of antibiotics.

Most yeast infections can be treated with a short course of anti-fungal cream or oral medication, but some cases may require longer, intense treatment. Women should avoid self-diagnosing and self-treating with over-the-counter medicine. It’s important to note that other infections, like those that are sexually transmitted, can resemble yeast infections. To avoid treating the wrong problem, it’s best to get a firm diagnosis from your doctor.

At Yale Medicine, we use a test that can recognize the most common Candida micro-organisms responsible for yeast infections, as well as more rare variants, such as C. glabrata and C. Krusei. “We can usually find the relevant species in less than one day, which allows for an accurate diagnosis and prompt symptom relief for our patients,” says Yale Medicine pathologist Angelique Levi, MD.  

What is a yeast infection?

The vaginal area has a mixture of healthy bacteria and Candida yeast cells that commingle harmlessly inside the vagina and outside on the skin. These yeast cells live normally in the mouth, throat, gut, and vagina without causing problems. 

But changes in the vaginal environment can lead to Candida outnumbering and overtaking healthy cells. This, in turn, can lead to a yeast infection. There are more than 20 species of different Candida yeast. The most common type that causes yeast infections is called Candida albicans

What can cause a yeast infection?

Yeast cells can grow quickly in the vagina if the population of healthy bacteria changes. Factors that can lead to an infection include the following:

  • Antibiotics, which decrease the levels of healthy bacteria in the body
  • Uncontrolled diabetes
  • Potential irritants, such as douching washes, spermicide, soaps, powders, or deodorants
  • Tight-fitting clothing and synthetic materials, such as bathing suits and sportswear
  • A weakened immune system
  • Pregnancy
  • Hormonal imbalance near the time of the menstrual cycle 

What are the symptoms of a yeast infection?

The symptoms of a yeast infection vary from person to person. Some people may have a yeast infection and show no symptoms at all. 

For those who are symptomatic, common clinical signs include itching, burning during urination, pain during sex, and soreness or inflammation around the vagina and vulva (the opening of the vagina). The severity of these symptoms ranges from mild to severe. Some women also experience a thick, white, and odorless vaginal discharge. 

How is a yeast infection diagnosed?

Your doctor will obtain a detailed medical history of your symptoms and changes in health. She or he will then perform a pelvic exam, and look at the vulva and inside the vagina for signs of inflammation, redness, and discharge. While it’s possible to diagnose a yeast infection based on these outward clinical signs, the doctor will also take a swab inside the vagina and send the sample to a lab for a confirmation. 

How is a yeast infection treated?

Some mild yeast infections go away on their own. One reason this can happen is that women’s vaginal pH balance tends to become more acidic during the menstrual cycle, making the vagina less hospitable to yeast cells, causing them to die off. If you and your doctor feel that treatment is in order, options include the following:

  • Fluconazole. This is a powerful anti-fungal oral medication that is usually given as a single dose and wipes out the yeast infection quickly.
  • Clotrimazole. This anti-fungal agent can come in the form of cream, ointment, or vaginal suppository. The treatment course can range from three to seven days and is available over the counter.

For complicated, severe, or recurrent yeast infections, your doctor may prescribe a combination of the above medicines and for a longer period of time.

Why are yeast infections more common during pregnancy?

During pregnancy, the female body undergoes various chemical and hormonal changes, which alter the balance of good bacteria and yeast in the vagina. While the infection can be uncomfortable for the mother, yeast infections do not harm the baby.

For a woman who is pregnant, a longer-than-normal course of treatment with clotrimazole may be recommended, given that yeast infections can resistant to treatment during pregnancy. It is important for the condition to be treated before the fetus’s delivery because it can be passed on in the form of oral thrush (a fungal infection inside the mouth or throat) of the infant. 

What makes Yale Medicine’s approach to treating yeast infections unique?

Our Ob/Gyns and other medical care team members have experience managing complicated or challenging cases of yeast infections. “For example, sometimes symptoms commonly noted with yeast infections such as vaginal itching and irritation can be severe,” says Yale Medicine gynecologist Sangini Sheth, MD. Perhaps the symptoms are caused by multiple different infections, not yeast alone, and therefore require additional treatments, she says. “A prolonged duration of symptoms may also require a different approach or close monitoring and follow-up.”