Inflammation of the breast parenchyma.

demographics: 10% of breastfeeding mothers ( ~ 2-4wks post-partum)

Aetiology:

• S. aureus (most common)
• Rarely other pathogens:
  • Streptococcus
  • S. epidermis
  • E. coli

Pathophysiology

Lactational (most common):

• Nipple fissures/ trauma facilitate bacteria entry (often from nostril/ throat of infant) into ducts during breastfeeding. Bacteria rapidly replication in the nutrient-rich milk environment
  • Prolonged breast engorgement, milk overproduction, insufficient milk drainage & milk stasis are favourable conditions for bacterial growth within ducts

Non-lactational cause:

• Nipple trauma (e.g nipple piercing)
• Strongly associated with diabetes, obesity and smoking

Risk factors

• Infrequent feeding
• Rapid weaning of baby (causing insufficient milk drainage)