Vaginal yeast infection is a disease characterized by signs, symptoms of vaginitis, vaginitis and presence of fungi (mainly Candida). Symptoms of vaginal yeast infection include: severe itching, painful urination and sexual intercourse, severe nausea (white cheese, no unpleasant odor except superinfection).

Candida albicans is the main causative agent of vaginal yeast infection. The rest are other yeasts, mostly C. glabrata. These fungi are part of the vaginal microenvironment without causing symptoms in some of healthy women. 

Classification of vaginal yeast infection: uncomplicated and complicated. Uncomplicated VYI occurs at a low frequency (<4 times per year), with mild to moderate symptoms, most likely caused by Candida albicans, and the infected women have a normal immune system. Complicated VYI is characterizd by one of the following: persistent inflammation, severe vaginitis, non-Candida albicans or co-morbidities such as diabetes mellitus, immunosupression, use of immunosuppressive drugs. 

Vaginal yeast infections occur mainly in women of reproductive age. The rate of vaginal yeast infections is linked to the amount of estrogen in the body, as increased estrogen levels increase glycogen levels in vaginal tissues, creating a carbon source for Candida. This explains why vaginal yeast infections mainly occur at reproductive age. 

The pathogenesis of vaginal yeast infection is associated with vaginal microflora imbalance, overgrowth of fungus, and invasion of fungal epithelial cells. Therefore, it is not considered a sexually transmitted disease.