Mastitis is inflammation of the breast usually caused by a bacterial infection. It can happen to any woman, although mastitis typically affects breastfeeding women more. Mastitis can leave a new mother feeling very tired and run-down. Add the illness to the demands of taking care of a newborn, and many women quit breastfeeding altogether. But mastitis can be treated with medicine, and you can continue to nurse your baby even though you have mastitis. In fact, breastfeeding usually helps to clear up the infection. Follow the links below to find WebMD's comprehensive coverage about how mastitis is contracted, what it looks like, how to treat it, and much more.