Vaginal yeast infection is an infection of the vagina, most commonly due to the fungus Candida albicans.

Most women will have a vaginal yeast infection at some time. Candida albicans is a common type of fungus. It is often present in small amounts in the vagina, mouth, digestive tract, and on the skin. Usually it does not cause disease or symptoms.

Candida and the many other germs or microorganisms that normally live in the vagina keep each other in balance. However, when the vagina has certain favorable conditions, the number of Candida albicans increases, leading to a yeast infection.

Some of these favorable conditions include:

• Antibiotics used to treat other types of infections change the normal balance between organisms in the vagina by decreasing the number of protective bacteria.
• Being pregnant, having diabetes, or being obese all create conditions that help yeast grow more easily.

Vaginal candidiasis is not a sexually transmitted disease. However, a small number of men will develop symptoms such as itching and a rash on the penis after having sexual contact with an infected partner.

Having many vaginal yeast infections may be a sign of other health problems. Other vaginal infections and discharges can be mistaken for a vaginal yeast infection.

Repeat infections that occur immediately after treatment, or a yeast infection that does not respond to any treatment, may be an early sign that a person is infected with HIV.