What antibiotics are recommended for the treatment of mastitis?

Antibiotics for Mastitis Treatment

For lactational mastitis, dicloxacillin or flucloxacillin (500 mg orally four times daily for 7-10 days) is the first-line antibiotic treatment due to its effectiveness against Staphylococcus aureus, the most common causative organism. 1

Diagnosis and Initial Management

• Mastitis is characterized by:

  • Focal breast tenderness
  • Erythema (redness)
  • Warmth
  • Fever (>38.5°C)
  • Malaise

• Regular milk removal through continued breastfeeding or expression is essential and should be encouraged even during antibiotic treatment 2

• Effective milk removal is the cornerstone of mastitis management and should be initiated before antibiotics

Antibiotic Selection Algorithm

First-line options:

• Dicloxacillin or flucloxacillin: 500 mg orally four times daily for 7-10 days
  • These penicillinase-resistant penicillins are effective against S. aureus, the most common pathogen 3, 1

For penicillin-allergic patients:

• Clindamycin: 300-450 mg orally three times daily for 7-10 days 4
  • Provides good coverage against most streptococci, pneumococci, and staphylococci

For severe cases or non-responsive to oral antibiotics:

• Consider IV antibiotics such as:
  • Ceftriaxone
  • Vancomycin (for suspected MRSA)
  • Combination therapy may be needed in complicated cases 5

Duration of Treatment

• Standard course: 7-10 days of antibiotics
• Continue antibiotics for the full course even if symptoms improve quickly
• Failure to complete the full course may lead to recurrence or abscess formation

Special Considerations

• MRSA prevalence is increasing, so treatment failure with traditional antibiotics may necessitate coverage for MRSA 1
• Approximately 10% of mastitis cases may progress to breast abscess, requiring drainage 1
• Continued breastfeeding during mastitis treatment is safe and recommended, as it helps with breast emptying 2

When to Consider Alternative Diagnoses

• If no improvement after 48 hours of appropriate antibiotic therapy:
  • Consider breast abscess formation (may require ultrasound evaluation)
  • Consider inflammatory breast cancer if symptoms persist beyond 1-2 weeks despite appropriate treatment 2
  • Obtain cultures if initial treatment fails

Evidence Quality Assessment

The evidence for antibiotic treatment in mastitis is surprisingly limited. A Cochrane review found insufficient high-quality evidence to confirm or refute antibiotic effectiveness for lactational mastitis 6. However, clinical practice guidelines consistently recommend antibiotics targeting S. aureus when symptoms are moderate to severe or don't improve with breast emptying alone 2.

Common Pitfalls to Avoid

1. Stopping antibiotics prematurely when symptoms improve
2. Advising women to stop breastfeeding during treatment
3. Failing to ensure complete breast emptying alongside antibiotic therapy
4. Not considering MRSA in cases of treatment failure
5. Missing inflammatory breast cancer, which can mimic mastitis but doesn't respond to antibiotics within 1-2 weeks 2

Remember that while antibiotics are important in treating mastitis, effective milk removal through continued breastfeeding or expression remains the cornerstone of management and should be emphasized alongside antibiotic therapy.