Vaginitis is inflammation of the vagina. In premenopausal women, infection is the most common cause. After menopause, a low level of estrogen often leads to vaginal atrophy (atrophic vaginitis). Vaginitis also can be the result of an allergic reaction to an irritating chemical, such as a spermicide, douche or bath soap.
Almost all infectious vaginitis is caused by one of three infections:
Bacterial vaginosis is a change in the type of bacteria that normally live in the vagina, and it is the most common cause of an abnormal vaginal discharge or an unpleasant vaginal odor. In bacterial vaginosis, normal Lactobacillus bacteria are replaced by other bacteria, including Prevotella, Mobiluncus, G. vaginalis, and Mycoplasma hominis. The exact reason for this change is unknown. In pregnant women, bacterial vaginosis can increase the risk of premature delivery.
Candida vaginal infections, also called vaginal yeast infections, typically are caused by the Candida albicans fungus. During a lifetime, 75% of all women are likely to have at least 1 Candida vaginal infection, and up to 45% have 2 or more. Women tend to be more susceptible to vaginal yeast infections if their bodies are under stress from poor diet, lack of sleep or illness, or if they are pregnant, taking antibiotics or birth control pills or douching too often. Women with diabetes or human immunodeficiency virus (HIV) are more likely to have recurrent yeast infections.
Trichomonas vaginitis, also called trichomoniasis, is a sexually transmitted disease (STD) caused by a microscopic one-celled organism called Trichomonas vaginalis. Trichomonas causes inflammation of the vagina, cervix and urethra in women. In pregnant women, Trichomonas infections also can increase the risk of premature rupture of the membranes and preterm delivery.