It can feel like itching or maybe even burning. Or you may ahve swelling so extreme, it leads to sores. Whether your symptoms are mild or severe, a yeast infection can be uncomfortable. Also known as vaginal candidiasis, yeast infections are caused by a fungus. It generally causes your vagina and vulva (the tissues at the opening of the vagina) to itch. There can also be discharge. Yeast infections are common. Three of every four women get one in their lifetime. And many women get it more than once. Knowing how to spot the signs and symptoms of a yeast infection can help you get the most effective treatment.