Candidiasis is the medical word for an infection of the body caused by yeast. This infection can occur in several places including the mouth, skin, and vagina. Actually, the yeast that cause candidiasis live on the surface of the skin, in the mouth, and in the vagina normally in many people. It is usually some sort of imbalance that causes the yeast to over proliferate and cause candidiasis.
For example, over cleaning is actually a common cause of vaginal candidiasis. This usually occurs in women who are using strong cleaning products to clean the vagina and, especially, in those who are douching. The douching kills off other healthy bacteria that live in the vagina, which allows the yeast to proliferate and cause itching and discharge.
Similarly, candidiasis can sometimes occur after sexual intercourse. Two possibilities here include the use of lubricants and other products that have the same effect as douching, and the other possibility is that your partners has yeast living on their skin and passes it to you.
Either way, candidiasis of the vagina is extremely common and not a sign usually of an underlying medical problem. It can be treated with simple usually over the counter anti fungal creams.