The underlying cause of mastitis is the stasis or pooling of milk within the breast, which leads to inflammation and eventually infection. This poor removal of milk can be caused by a variety of factors such as limiting the time that baby spends at the breast, infrequent feedings, skipping feedings, plugged duct, or even oversupply. Although milk stasis is the leading cause of mastitis, any break in the skin can become an entry point for an infectious process to start. This damage to the nipple is characterized by cracking, scabbing, or bleeding nipples usually due to poor latch-on technique. Finally, stress, fatigue, anemia, or a weakened immune system may cause a mom to feel run-down and become susceptible to a breast infection.