Cause.

Yeast infection is caused by a fungus called Candida. It is found in small numbers in the normal vagina. However, when the balance of bacteria and yeast in the vagina is altered, the yeast may overgrow and cause symptoms.

Some types of antibiotics increase your risk of a yeast infection. The antibiotics kill normal vaginal bacteria, which keep yeast in check. The yeast can then overgrow. A woman is more likely to get yeast infections if she is pregnant or has diabetes. Overgrowth of yeast also can occur if the body’s immune system, which protects the body from disease, is not working well. For example, in women infected with human immunodeficiency virus (HIV), yeast infections may be severe. They may not go away, even with treatment, or may recur often. In many cases, the cause of a yeast infection is not known.

Causes

Vulvovaginitis can affect women of all ages and is very common. Specific forms of vaginitis are:

[edit] Infection

Infectious vaginitis accounts for 90% of all cases in reproductive age women and is represented by the triad:

    * Candidiasis: vaginitis caused by Candida albicans (a yeast).
    * Bacterial vaginosis: vaginitis caused by Gardnerella (a bacterium).
    * Trichomoniasis: vaginitis caused by Trichomonas vaginalis (a parasite).

Other less common infections are caused by gonorrhea, chlamydia, mycoplasma, herpes, campylobacter and some parasites.[1]

Vaginal infection are often (varies between countries between 20 to 40% of vaginal infections) a mix of various etiologies, which present challenging cases for treatment. Indeed, when only one cause is treated, the other pathogens can gain in resistance and induce relapses and recurrences. The key factor is therefore to get a precise diagnosis and treat with broad spectrum anti-infective (often also inducing adverse effects).