Breast Abscess

Basics

Description

  • Breast abscess: infection of the breast bud or tissue associated with localized pus and inflammation
  • Mastitis: infection of the breast tissue observed primarily during lactation

Epidemiology

  • 3–11% of women with breastfeeding mastitis develop a breast abscess.
  • Affects primarily infants (peak age 1 to 6 weeks) and adolescents
  • Bilateral abscesses, seen among neonates, are rare.
  • Male-to-female ratio is 1:2 in neonates.

Risk Factors

  • In lactating teens, primiparity
  • Gestational age >40 weeks
  • Mastitis
  • Obesity, black race, tobacco use

General Prevention

  • Avoid breast manipulation (including piercing).
  • In lactating teens, establish good breastfeeding techniques.
  • Recognize and treat mastitis early.

Pathophysiology

  • Newborns
    • Trauma, breast hypertrophy from maternal estrogen, or compromised host defenses enable spread of bacteria that often colonize the nasopharynx and umbilicus.
    • The bacteria and/or its toxin, in turn, cause(s) subcutaneous destruction and loculated pus formation.
  • Adolescents/adults: Trauma (e.g., sexual manipulation, nipple rings, tight-fitting bras, incorrect latching during breastfeeding), contiguous spread of a local infection (e.g., mastitis, acne), or underlying structural abnormalities (e.g., mammary duct ectasia, epidermal cysts) cause breast tissue edema and destruction by bacteria and/or its toxin.
  • When mastitis is associated with breastfeeding, the inflammation inhibits milk release. The stasis of milk, in turn, may allow for bacterial proliferation.

Etiology

  • Newborn infection: Staphylococcus aureus (most common), group A or B Streptococcus, Bacteroides species, and gram-negative enteric bacteria, including Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Salmonella species
  • Adolescent/adult infection: S. aureus (most common) with up to 19% being methicillin-resistant, E. coli, P. aeruginosa, Mycobacterium tuberculosis, Neisseria gonorrhoeae, and Treponema pallidum are infrequent pathogens.

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