Breast abscess

What it is

Cracking of the skin around the nipple allows bacteria from the skin surface to enter the breast duct, where it grows and attracts inflammatory cells. Those cells release substances to fight the infection but also cause breast tissue swelling and increased blood flow. That is mastitis, and it may present with abscess. Milk stasis is one of the causes.

Mastitis is split by whether the woman is lactating. Lactating mastitis is the more common and is due to staph. aureus. Non-lactating mastitis is due to streptococcus and has three forms: centrally, in the periareolar region, which is periductal mastitis; peripheral; and granulomatous lobular mastitis. Milk stasis is described elsewhere as the initiating factor, with inadequate milk removal predisposing to the bacterial growth of infectious mastitis, and mastitis affects around 1 in 10 breast feeding women; left untreated it may develop into a breast abscess, which generally requires incision and drainage.

How it presents

Fever, pain, swelling, redness and a hot breast, and it may present with abscess. In taking the history, fever points to abscess, erythema to abscess or mastitis or cancer, and malaise and lymphadenopathy to abscess or cancer.

The forms differ:

• Periductal mastitis: young, mean age 30 years, periareolar inflammation with or without a mass, active inflammation around a non dilated duct unlike duct ectasia, and confused with duct ectasia; smoking is important in the aetiology
• Peripheral: less common, associated with DM, RA, steroids treatment and trauma; pilonidal abscess has been reported, and it is associated with granulomatous lobular mastitis
• Granulomatous lobular mastitis: young multiparous women, mass with or without erythema so that it mimics cancer, mostly unilateral, high recurrent and troublesome; causes are idiopathic, TB and sarcoidosis

In the puerperium, mastitis and breast abscess sit in the differential of postpartum pyrexia, which is a temperature of 38 on any 2 of the first 10 postpartum days, excluding the first 24 hours, alongside endometritis and wound infection. The painful breast comes with fever, malaise and a tender, red, swollen and hard area, usually in a wedge-shaped distribution, and the suspected abscess is a history of recent mastitis with a painful, swollen lump in the breast with redness, heat and swelling of the overlying skin. Breast engorgement is the other cause of breast pain in a breastfeeding woman: it appears in the first few days, almost always affects both breasts, is worse just before a feed, and any fever usually settles within 24 hours.