Yeast vaginitis can be caused by several reasons.

First, women are prone to yeast vaginitis during their specific physiological periods because the vaginal environment becomes more acidic during menstruation, which favors the growth of yeast and thus causes yeast vaginitis.

Second, medicinal factors may play a role. The use of a large amount of antibiotics by women can lead to a disruption of the vaginal flora, allowing yeast to proliferate. Additionally, individuals with diabetes are also more susceptible to yeast vaginitis.

Third, contact with items infected with yeast can lead to yeast vaginitis. It could also occur during unhygienic sexual activities. Other causes may include the growth of yeast in underwear, which can subsequently spread to the vagina, leading to yeast vaginitis.