Empiric Therapy Regimens
Outpatient options includes the following:
Dicloxacillin 500 mg PO QID for 10-14 days or
Cephalexin 500 mg PO QID for 10-14 days or
Amoxicillin-clavulanate 500 mg PO TID or 875 mg PO BID for 10-14 days
If beta-lactam allergy:
Clarithromycin 500 mg PO BID for 10-14 days (or see following section)
If suspected community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection:
Clindamycin 300 mg PO TID for 10-14 days or
Doxycycline 100 mg PO BID for 10-14 days (pregnancy Category D and secreted in breast milk; do not use in pregnancy or if breastfeeding)
Options includes the following:
If beta-lactam allergy or MRSA suspicion:
For rare strains or refractory cases:
Linezolid 600 mg PO/IV q12h for 10-14 days (pregnancy category C; unknown if secreted in breast milk) or
Tigecycline 100-mg IV infusion, then 50-mg IV infusion q12h for 5-14 days (pregnancy Category D and unknown if secreted in breast milk; do not use in pregnancy or if breastfeeding) or
Daptomycin 4 mg/kg IV infusion q24h for 7-14 days (pregnancy category B; secreted in breast milk but poorly bioavailable orally; use caution if breastfeeding) or
Emerging treatment options
These drugs have been approved by the FDA for treatment of soft-tissue infections but have not yet been assessed specifically for efficacy in treating breast infections.
Ceftaroline 600 mg IV q12h; infuse over 5-60 minutes for 5-14 days (approved to treat MRSA infections; pregnancy Category B, unknown if secreted in breast milk) or
Dalbavancin: (1) 1-dose regimen of 1500 mg IV or (2) 2-dose regimen of 1000 mg IV followed 1 week later by 500 mg IV; infuse IV over 30 minutes (pregnancy category C, unknown if secreted in breast milk)
If an abscess develops, consider irrigation and debridement along with IV antibiotics.
Patients with recurrent mastitis
Rule out abscess with ultrasonography.
Consider choosing an antibiotic to cover methicillin-resistant Staphylococcus aureus (MRSA): clindamycin, trimethoprim-sulfamethoxazole, or vancomycin. 
Patients with nonpuerperal mastitis
Consider the possibility of cancer.
A ruptured cyst may be associated with inflammation.
The mastitis may be self-limited, and antibiotics therefore of questionable benefit.
If antibiotic treatment is needed, provide it as for lactating women.