Two of the most common causes are related to organisms that live in your vagina. They can have very similar symptoms. Yeast infections are an overgrowth of the yeast that you normally have in your body. Bacterial vaginosis happens when the balance of bacteria is thrown off. With both conditions, you may notice white or grayish discharge. How can you tell them apart? If there's a fishy smell, bacterial vaginosis is a better guess. If your discharge looks like cottage cheese, a yeast infection may be to blame. That's also more likely to cause itching and burning, though bacterial vaginosis might make you itchy, too. And you could have both at the same time.