What is the recommended treatment for a lactating woman with mastitis?

Treatment of Mastitis in Lactating Women

For lactating women with mastitis, initiate a 1-2 day trial of conservative management (NSAIDs, ice, continued breastfeeding) before starting narrow-spectrum antibiotics if symptoms do not improve within 12-24 hours. 1

Initial Conservative Management (First 12-24 Hours)

Most mastitis cases are inflammatory rather than infectious, with 14-20% resolving spontaneously without antibiotics. 1 The initial approach should include:

• Continue breastfeeding from the affected breast - this helps resolve the condition and does not pose risk to the infant 2, 1
• NSAIDs for pain and inflammation 1, 3
• Ice application to the affected area 1, 3
• Avoid overstimulation - minimize excessive pumping, aggressive breast massage, and heat application, as these worsen the condition 3

This conservative approach allows many cases to resolve without antibiotics, avoiding unnecessary antimicrobial exposure. 1

When to Start Antibiotics

Add antibiotics if symptoms do not improve within 12-24 hours of conservative management, as delaying treatment risks abscess formation (occurs in approximately 10% of mastitis cases). 2, 1

First-Line Antibiotic Selection

Dicloxacillin 500 mg orally four times daily is the preferred agent for methicillin-susceptible Staphylococcus aureus, which causes the majority of infectious mastitis cases. 2, 1

Cephalexin 500 mg orally four times daily is an equally effective alternative, particularly useful for penicillin-allergic patients. 2, 1 Both agents are safe during breastfeeding with minimal transfer to breast milk. 1

Alternative options include:

• Amoxicillin/clavulanic acid - a broad-spectrum option safe during breastfeeding 2
• Erythromycin or azithromycin - for penicillin-allergic patients, but note very low risk of infantile hypertrophic pyloric stenosis if macrolides are used during the first 13 days of infant life 2

MRSA Coverage Considerations

Consider MRSA coverage with clindamycin (use with caution due to potential GI side effects in infant) if: 2, 1

• High local MRSA prevalence
• Previous MRSA infection
• No response to first-line beta-lactam antibiotics within 48-72 hours

Monitoring and Red Flags

Reevaluate within 48-72 hours if symptoms worsen or do not improve to rule out abscess formation. 2 Perform ultrasonography to identify abscesses in patients with worsening or recurrent symptoms. 3

Hospital admission is warranted for patients with systemic symptoms suggesting sepsis risk, such as high fever and chills. 1

Critical Warning Signs

Symptoms persisting beyond 1 week of appropriate antibiotics may indicate inflammatory breast cancer, particularly in non-lactating women, and warrant urgent evaluation including ultrasound and possible biopsy within 48 hours. 1 Red flags include erythema occupying at least one-third of breast surface or peau d'orange appearance. 1

Common Pitfalls to Avoid

• Do not discontinue breastfeeding - continued breastfeeding from the affected breast is therapeutic and safe for the infant 2, 1
• Avoid excessive pumping and aggressive breast massage - these worsen inflammation through overstimulation 3
• Do not delay antibiotics beyond 24 hours if conservative measures fail - this increases abscess risk 2, 1
• Never use methotrexate during breastfeeding due to potential accumulation in neonatal tissues 1