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.
The exudate is then sent for microbiological analysis for identification of the pathogen and determination of its antibiotic sensitivity profile, which may in turn give an indication for changing the antibiotics. At follow-up, a mammography is performed if the condition has resolved; otherwise the ultrasound-guided fine-needle aspiration with lavage and microbiological analysis is repeated. If three to five aspirations still do not resolve the condition, percutaneous drainage in combination with placement of an indwelling catheter is indicated, and only if several attempts at ultrasound-guided drainage fail, surgical resection of the inflamed lactiferous ducts (preferably performed after the acute episode is over). It is noted, however, that even the excision of the affected ducts does not necessarily prevent recurrence.Nonpuerperal breast abscesses have a higher rate of recurrence compared to puerperal breast abscesses. There is a high statistical correlation of nonpuerperal breast abscess with diabetes mellitus (DM). On this basis, it has recently been suggested that diabetes screening should be performed on patients with such abscess.Although there are a number of recommendations regarding the treatment of breast abscesses, a 2015 review found insufficient evidence of whether needle aspiration is comparable to incision and drainage, or whether antibiotics should generally be given to women undergoing incision and drainage. Prognosis
Temperature and severity of symptoms at presentation do not predict outcome; women with sore or damaged nipples may need special attention. Epidemiology
Mastitis is quite common among breastfeeding women. The WHO estimates that although incidences vary between 2.6% and 33%, the prevalence globally is approximately 10% of breastfeeding women.