Overview

A vaginal yeast infection is a fungal infection that causes irritation, discharge and intense itchiness of the vagina and the vulva — the tissues at the vaginal opening.

Also called vaginal candidiasis, vaginal yeast infection affects up to 3 out of 4 women at some point in their lifetimes. Many women experience at least two episodes.

A vaginal yeast infection isn't considered a sexually transmitted infection. But, there's an increased risk of vaginal yeast infection at the time of first regular sexual activity. There's also some evidence that infections may be linked to mouth to genital contact (oral-genital sex).

Medications can effectively treat vaginal yeast infections. If you have recurrent yeast infections — four or more within a year — you may need a longer treatment course and a maintenance plan.

Symptoms

Yeast infection symptoms can range from mild to moderate, and include:

  • Itching and irritation in the vagina and vulva
  • A burning sensation, especially during intercourse or while urinating
  • Redness and swelling of the vulva
  • Vaginal pain and soreness
  • Vaginal rash
  • Thick, white, odor-free vaginal discharge with a cottage cheese appearance
  • Watery vaginal discharge

Complicated yeast infection

You might have a complicated yeast infection if:

  • You have severe signs and symptoms, such as extensive redness, swelling and itching that leads to tears, cracks or sores
  • You have four or more yeast infections in a year
  • Your infection is caused by a less typical type of fungus
  • You're pregnant
  • You have uncontrolled diabetes
  • Your immune system is weakened because of certain medications or conditions such as HIV infection

When to see a doctor

Make an appointment with your doctor if:

  • This is the first time you've had yeast infection symptoms
  • You're not sure whether you have a yeast infection
  • Your symptoms aren't relieved after treating with over-the-counter antifungal vaginal creams or suppositories
  • You develop other symptoms

Causes

The fungus candida albicans is responsible for most vaginal yeast infections.

Your vagina naturally contains a balanced mix of yeast, including candida, and bacteria. Certain bacteria (lactobacillus) act to prevent an overgrowth of yeast.

But that balance can be disrupted. An overgrowth of candida or penetration of the fungus into deeper vaginal cell layers causes the signs and symptoms of a yeast infection.

Overgrowth of yeast can result from:

  • Antibiotic use, which causes an imbalance in natural vaginal flora
  • Pregnancy
  • Uncontrolled diabetes
  • An impaired immune system
  • Taking oral contraceptives or hormone therapy that increase estrogen levels

Candida albicans is the most common type of fungus to cause yeast infections. Yeast infections caused by other types of candida fungus can be more difficult to treat, and generally need more-aggressive therapies.

Risk factors

Factors that increase your risk of developing a yeast infection include:

  • Antibiotic use. Yeast infections are common in women who take antibiotics. Broad-spectrum antibiotics, which kill a range of bacteria, also kill healthy bacteria in your vagina, leading to overgrowth of yeast.
  • Increased estrogen levels. Yeast infections are more common in women with higher estrogen levels — such as pregnant women or women taking high-dose estrogen birth control pills or estrogen hormone therapy.
  • Uncontrolled diabetes. Women with poorly controlled blood sugar are at greater risk of yeast infections than women with well-controlled blood sugar.
  • Impaired immune system. Women with lowered immunity — such as from corticosteroid therapy or HIV infection — are more likely to get yeast infections.

Prevention

To reduce your risk of vaginal yeast infections, wear underwear that has a cotton crotch and doesn't fit too tightly.

It might also help to avoid:

  • Tight-fitting pantyhose
  • Douching, which removes some of the normal bacteria in the vagina that protect you from infection
  • Scented feminine products, including bubble bath, pads and tampons
  • Hot tubs and very hot baths
  • Unnecessary antibiotic use, such as for colds or other viral infections
  • Staying in wet clothes, such as swimsuits and workout attire, for long periods of time

Oct. 30, 2018
References
  1. AskMayoExpert. Vulvovaginitis. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2018.
  2. Ferri FF. Vaginitis, fungal. In: Ferri's Clinical Advisor 2019. Philadelphia, Pa.: Elsevier; 2019. https://www.clinicalkey.com. Accessed Aug. 26, 2018.
  3. Lobo RA, et al. Genital tract infections: Vulva, vagina, cervix, toxic shock syndrome, endometritis, and salpingitis. In: Comprehensive Gynecology. 7th ed. Philadelphia, Pa.: Elsevier; 2017. https://www.clinicalkey.com. Accessed Aug. 26, 2018.
  4. Cohen J, et al., eds. Vaginitis, vulvitis, cervicitis, and cutaneous vulval lesions. In: Infectious Diseases. 4th ed. Philadelphia, Pa.: Elsevier; 2017. https://clinicalkey.com. Accessed Aug. 26, 2018.
  5. Butler Tobah YS (expert opinion). Mayo Clinic, Rochester, Minn. Sept. 5, 2018.
  6. Blostein F, et al. Recurrent vulvovaginal candidiasis. Annals of Epidemiology. 2017;27:575.
  7. Bope ET, et al. Vulvovaginitis. In: Conn's Current Therapy 2018. Philadelphia, Pa.: Elsevier; 2018. https://www.clinicalkey.com. Accessed Aug. 26, 2018.
  8. Vaginal yeast infections. Office on Women's Health. https://www.womenshealth.gov/a-z-topics/vaginal-yeast-infections. Accessed Aug. 26, 2018.