I have to agree 100% with Namahottie. She has given EXCELLENT advice, it is accurate. Your girl should be seen by a health care provider if the infections keep recurring in order to rule out any malignant causes. Preferrably by one who can communicate with her in her language (I’m guessing that’s English).
Yeast infections occur because of an imbalance in the environment (pH) of the vagina. Some of the things that alter the environment are: douching, perfumed soaps or personal products, semen, tight fitting underwear that doesn’t breathe, the pill. Other possibilities are pregnancy, diabetes, hypothyroidism, immunosuppressed status (HIV or steroid medication) all of these can cause repeated yeast overgrowth. Symptoms/signs are cheesy white discharge, sweet smell - of course an awful itch.
Bacterial Vaginosis (BV), another vaginal infection mentioned, is caused by bacteria and treated with antibiotics. As above, something has occurred to alter the normal environment. The lactobacilli bacteria (good guys) have been replaced by anaerobic bacteria (bad guys). Lactobacilli produce hydrogen peroxide as a byproduct of their metabolism - this protects the vagina from other microbes. Symptoms/signs are unpleasant fishy or musty odor especially after sex, thin gray-white discharge, and itchiness.
Could be Trichomoniasis (Trich) which is an STD - a protozoan parasite found in the men and women at genitourinary sites. 10-25% vaginal infections in U.S. caused by this little bugger. Symptoms/signs are vaginal discharge that is usually copious, watery and frothy, itchiness, odor. Men usually have NO SYMPTOMS. So, if a person has this both sex partners need to be treated.
The above 3 possibilities are the most common causes of itchy hoochie. The way many OB/GYN’s diagnose these is by taking a specimen of the vaginal discharge and rubbing it on a few microscope slides, and then applying various chemicals and fixers and looking at it all under the microscope. It’s fast and easy to do in the office if the office is adequately equipped. All 3 are easy to treat.
For prevention reference Namahottie’s posts.