Mastitis is also called milk fever. Mastitis is a bacterial infection within the duct or duct system in the breasts.Germs enter from the baby's mouth into the milk duct through your sore nipples. This is more common among first time breastfeeding mothers. The baby is not affected on feeding from the infected breast.
You must breastfeed your baby as often as possible to drain milk from the infected breast. If you find your baby's suckling too painful, you must use a breast pump to express your milk. You can try different breast feeding positions to drain different ducts during each feeding and clear the blockage. Incorrect breastfeeding latching may also trigger this.
Remember to get yourself treated immediately for this to prevent the development of breast abscess. Your doctor may advise you to take antibiotics, pain relievers, heat applications or bed rest.