What disease could you possibly have if you excrete white substances from your vagina and its really itchy?

Itchy, white discharge from the vagina usually indicates some form of vaginitis. The main causes of vaginitis are yeast, bacterial vaginosis, and trichomonas. Yeast vaginitis typically causes the symptoms you mention, but the best way to be sure is to see a health care provider who can examine you and look at your discharge under a microscope.   Less commonly, vaginal discharge and itching may be from an allergy to latex condoms or a sex toy, or from irritation caused by use of a product that comes in contact with either the vulva or vagina. Examples of common irritants are soap, lubricants, feminine hygiene products, bath salts or aromatherapy bath products, laundry detergent and fabric softeners. See other questions in this section, specifically Yeast? Oral Sex? and Terribly itchy.