Breast infection

Mastitis is an inflammatory condition of the breast. This may or may not be accompanied by infection of the breast (1).

Symptoms suggestive of an infection may be seen in both infectious and non infectious mastitis although pyrexia (flu like) symptoms is more likely to persist for longer than 24 hours in infectious mastitis and may also produce considerable breast discomfort (1).

Clinical features of mastitis include:

• red, swollen, inflamed area of the breast
• breast is hot to touch
• fever of >38°C
• flu-like symptoms which include chills, headache, muscle aches
• painful lump caused by a blocked duct (1)

In around 3% of patients, mastitis may be complicated by a breast abscess (1).

Common organisms responsible for mastitis and breast abscess are

• Staphylococcus aureus – most common
• Esherichia coli (or other gram negative bacteria)
• Bacteroides
• streptococci (alpha, beta and non-haemolytic) (1)

The majority of breast infections may be divided into four groups:

• neonatal infection
• infections in lactating women
• infections in non-lactating women
• infections resulting from localised skin infection

Key points with respect to management in adults (2):

• S. aureus is the most common infecting pathogen. Suspect if woman has:
  • a painful breast;
  • fever and/or general malaise;
  • a tender, red breast
  • antibiotic therapy:
    • flucloxacillin 500mg QDS 10 to 14 days
    • if penicillin allergy:
      • erythromycin 250mg to 500mg QDS for 10 to 14 days OR
      • clarithromycin 500mg BD for 10 to 14 days
• breastfeeding:
  • oral antibiotics are appropriate, where indicated.
  • women should continue feeding including from the affected breast.

Reference:

• (1) Guidelines and Audit Implementation Network (GAIN) 2009. Guidelines on the treatment, management & prevention of mastitis
• (2) Public Health England (June 2021). Managing common infections: guidance for primary care