Different types of vaginitis have different causes and risk factors. Bacterial vaginosis (BV) occurs when the “bad” bacteria in the vagina become too numerous. Although BV can be transmitted through sexual intercourse, it can also affect individuals who are not sexually active. Therefore, it is not generally considered a sexually transmitted disease (STD). Other risk factors include:

• Having a new sex partner
• Having multiple sex partners
• Having unprotected sex
• Douching
• Exposure to irritants, such as bubble baths, deodorized tampons, feminine hygiene sprays, harsh soaps and others
• Using an intrauterine device (IUD) for contraception

In addition, race is a significant risk factor for BV. African-American women are three times more likely to develop the condition than other women, although the reason for this disparity remains unclear.

Yeast infection is caused by an overabundance of a microscopic Candida fungus in the vagina. Yeast infections are not considered STDs although, very rarely, they may be spread to male partners through sexual intercourse. Yeast infection may be caused by a variety of factors, including, but not limited to:

• Hormonal changes, including those associated with birth control pills and pregnancy
  
  
• Diabetes, HIV and other conditions that affect the immune system
  
  
• Medications, such as steroids and antibiotics
  
  
• Vaginal contraceptives
  
  
• Feminine hygiene products, such as deodorants and sprays
  
  
• Bubble baths

Trichomoniasis typically occurs when the Trichomonas vaginalis parasite is spread to the vagina through sexual intercourse with a partner who has the infection. Because the parasite can live several hours on damp washcloths, towels and bathing suits, it can be spread if these items are shared among individuals. Trichomoniasis is most common in individuals who are at their sexual peak. Risk factors for trichomoniasis include:

• Unprotected sex
• Infection with another STD
• Having multiple sex partners

Atrophic vaginitis usually results from a decline in estrogen (a female reproductive hormone) levels after menopause. Reduction of the hormone may cause changes in the skin around the vagina, vulva, urethra and/or bladder. Although menopause is the primary cause of this condition, atrophic vaginitis may also be associated with:

• Breastfeeding
  
  
• The use of injectable contraceptives
  
  
• Oophorectomy (also called ovariectomy, the surgical removal of the ovaries)

Noninfectious vaginitis may be caused by any of the following products, which can irritate the skin around the vagina or cause an allergic reaction:

• Vaginal sprays
• Douches
• Perfumed soaps
• Scented detergents
• Spermicidal products