However, only about 0.4–0.5% of breastfeeding mothers develop an abscess.Some predisposing factors are known but their predictive value is minimal. It appears that proper breastfeeding technique, frequent breastfeeding and avoidance of stress are the most important factors that can be influenced. Light cases of mastitis are often called breast engorgement; the distinction is overlapping and possibly arbitrary or subject to regional variations. Non pregnancy related
The term nonpuerperal mastitis describes inflammatory lesions of the breast occurring unrelated to pregnancy and breastfeeding. This article includes description of mastitis as well as various kinds of mammary abscesses. Skin related conditions like dermatitis and foliculitis are a separate entity. Names for non-puerperal mastitis are not used very consistently and include mastitis, subareolar abscess, duct ectasia, periductal inflammation, Zuskas disease and others. Periductal mastitis is a form of nonlactational mastitis, and is characterized by inflammation of the subareolar ducts. Although the cause of periductal mastitis is currently unknown, it is predicted that smoking may be related. This condition is mainly seen in young women but can also be seen in men. Signs and symptoms
Lactation mastitis usually affects only one breast and the symptoms can develop quickly. It develops into three stages, from the initial stage, the pus formation stage, to the restoration stage.
There is a possibility that infants carrying infectious pathogens in their noses can infect their mothers; the clinical significance of this finding is still unknown. Mastitis and breast abscesses can also be caused by direct trauma to the breast. Such injury can occur for example during sports activities or due to seat belt injury. Mastitis can also develop due to contamination of a breast implant or any other foreign body, for example after nipple piercing. In such cases, the removal of the foreign body is indicated.Women who are breastfeeding are at risk for developing mastitis especially if they have sore or cracked nipples or have had mastitis before while breastfeeding another baby. Also, the chances of getting mastitis increases if women use only one position to breastfeed or wear a tight-fitting bra, which may restrict milk flow  Difficulties in getting a nursing infant to latch on to the breast can also increase the risk for mastitis.Women with diabetes, chronic illness, AIDS, or an impaired immune system may be more susceptible to the development of mastitis. Infection
Some women (approximately 15%) will require antibiotic treatment for infection which is usually caused by bacteria from the skin or the babys mouth entering the milk ducts through skin lesions of the nipple or through the opening of the nipple. Infection is usually caused by Staphylococcus aureus. Infectious pathogens commonly associated with mastitis are Staphylococcus aureus, Streptococcus spp. and Gram-negative bacilli such as Escherichia coli.