Yeast infection is a form of vaginitis, an inflammation or infection of the vagina. During a lifetime, almost 75 percent of all women are likely to have at least one vaginal yeast infection and nearly half have two or more according to the U.S. Centers for Disease Control and Prevention (CDC). Yeast infections can also affect pubescent girls, and, in rare instances, it may be transmitted to men through sexual intercourse.

Small numbers of Candida, a single-celled fungus, are always present in a woman’s vagina. Normally, the acidic environment of the vagina prevents the yeast from over growing. When the environment becomes disturbed and the acidic level is too low, too many organisms can grow, causing a yeast infection.

Candida albicans, which also grows normally in the mouth and digestive tract, can spread to other parts of the body, including the skin, mucous membranes, esophagus and other areas. It can cause life-threatening systemic infections, such as sepsis (infection of the blood), especially in individuals with a weakened immune system. This population includes pregnant women, individuals with diabetes and HIV-infected people.

Approximately 5 percent of patients with vaginal yeast infections develop a condition called recurrent vulvovaginal candidiasis (RVVC). RVVC is classified as more than three symptomatic vaginal yeast infections over the course of one year. Patients who experience RVVC should notify their gynecologist (a physician who specializes in treating disorders of the female reproductive system) who will attempt to identify the underlying cause of the condition.

Patients with a diagnosed yeast infection who use latex condoms or a diaphragm for birth control should discuss treatment with the physician. Some common medications used to treat yeast infections can weaken latex, and potentially compromise the birth control method. For this reason, another form of contraception may be necessary during the treatment period.

It is difficult to determine the percentage of women who have been affected by yeast infections because individuals do not always have recognizable symptoms and home treatment often goes unreported. Unlike other forms of vaginitis, such as trichomoniasis, yeast infections are not considered sexually transmitted diseases.

Proper diagnosis is important for effective treatment of yeast infections. Because the symptoms are similar to other conditions, yeast infections must be diagnosed correctly to rule out other illnesses or diseases. Left untreated, symptoms of yeast infection – which can be very uncomfortable – may persist. In severe cases, an untreated yeast infection can lead to more serious conditions, such as sepsis.