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. It's a type of vaginitis, or inflammation of the vagina.
Vaginal yeast infection (also called vaginal candidiasis) affects up to 3 out of 4 women at some point in their lifetimes. Many women experience at least two episodes.
Although a vaginal yeast infection isn't considered a sexually transmitted infection, you can spread the fungus through mouth to genital contact. 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.
Yeast infection symptoms can range from mild to moderate and include:
- Itching and irritation in the vagina and the tissues at the vaginal opening (vulva)
- A burning sensation, especially during intercourse or while urinating
- Redness and swelling of the vulva
- Vaginal pain and soreness
- Vaginal rash
- Watery vaginal discharge
- Thick, white, odor-free vaginal discharge with a cottage cheese appearance
Complicated yeast infection
You might have a complicated yeast infection if:
- You have severe symptoms, such as extensive redness, swelling and itching that leads to tears or cracks (fissures) or sores
- You have four or more yeast infections in a year
- Your infection is caused by a type of candida other than Candida albicans
- 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 don't disappear after treating with over-the-counter antifungal vaginal creams or suppositories
- You develop other symptoms
The fungus candida causes a vaginal yeast infection. Your vagina naturally contains a balanced mix of yeast, including candida, and bacteria. Lactobacillus bacteria produce acid, which prevents yeast overgrowth. That balance can be disrupted and lead to a yeast infection. Too much yeast in your vagina causes vaginal itching, burning and other classic signs and symptoms of a yeast infection.
Overgrowth of yeast can result from:
- Antibiotic use, which decreases lactobacillus bacteria in your vagina and changes the pH of your vagina
- Uncontrolled diabetes
- Impaired immune system
- Taking oral contraceptives or hormone therapy, which increases estrogen levels
Candida albicans is the most common type of fungus to cause yeast infections. Sometimes, other types of candida fungus are to blame. Common treatments usually cure a Candida albicans infection. Yeast infections caused by other types of candida fungus can be more difficult to treat, and need more aggressive therapies.
A yeast infection might happen after certain sexual activities, especially oral-genital sexual contact. However, a yeast infection isn't considered a sexually transmitted infection. Even women who aren't sexually active can develop yeast infections.
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 organisms.
- Increased estrogen levels. Yeast infections are more common in women with an increased estrogen level. This can include women who are pregnant, or those who are taking high-dose estrogen birth control pills or estrogen hormone therapy.
- Uncontrolled diabetes. Women with diabetes who have poorly controlled blood sugar levels are at greater risk of yeast infections than women with well-controlled diabetes.
- Impaired immune system. Women with lowered immunity — such as from corticosteroid therapy or HIV infection — are more likely to get yeast infections.
- Sexual activity. Although yeast infections aren't considered sexually transmitted infections, sexual contact can spread the candida fungus.
To reduce your risk of vaginal yeast infections:
- Wear cotton underwear and loose-fitting pants or skirts.
- Avoid tight-fitting underwear or pantyhose.
- Immediately change out of wet clothes, such as swimsuits or workout attire.
- Stay out of hot tubs and very hot baths.
- Avoid unnecessary antibiotic use, such as for colds or other viral infections.