What is the first-line treatment for mastitis?

First-Line Treatment for Non-Breastfeeding Mastitis

For non-breastfeeding women with mastitis, initiate empiric antibiotic therapy with dicloxacillin or cephalexin targeting Staphylococcus aureus, combined with NSAIDs and ice application. 1

Clinical Recognition

Non-breastfeeding mastitis presents distinctly from lactational mastitis:

• Focal, unilateral breast pain that is precisely localizable and reproducible, with inflammatory signs including induration, redness, warmth, and potentially fever 1
• Predominantly subareolar or nipple region involvement, often associated with duct ectasia and periductal inflammation 1
• Strong association with heavy smoking in many cases 1

Antibiotic Selection

The American College of Radiology recommends specific anti-staphylococcal agents:

• Dicloxacillin as first-line therapy 1
• Cephalexin as an alternative first-line option 1
• These agents specifically target Staphylococcus aureus, the predominant pathogen in non-lactational mastitis 2, 3

Critical distinction: Unlike lactational mastitis where conservative management may be attempted first, non-lactational mastitis is more likely infectious from the outset and should not have delayed antibiotic initiation 1

Supportive Care

Combine antibiotics with:

• NSAIDs for pain and inflammation control 1
• Ice application to reduce swelling 1

Monitoring and Complications

Approximately 10% of mastitis cases progress to breast abscess 1, requiring vigilant monitoring:

• Mandatory ultrasonography if symptoms worsen or recur despite appropriate antibiotic therapy 1
• Surgical drainage or needle aspiration required once abscess forms 1
• Early antibiotic treatment helps prevent abscess formation 1

Red Flags Requiring Urgent Evaluation

Do not assume all breast inflammation is simple mastitis. Exclude inflammatory breast cancer if: 1

• Erythema occupies at least one-third of the breast surface 1
• Peau d'orange is present 1
• Symptoms persist beyond 1 week of appropriate antibiotics 1
• History of recurrent "mastitis" not responding to antibiotics 1

If inflammatory breast cancer is suspected:

• Urgent ultrasound within 24-48 hours to identify mass or abscess 1
• Core needle biopsy within 48 hours if mass detected 1
• Punch biopsy of skin plus diagnostic mammogram 1
• Multidisciplinary oncology referral within 24-48 hours 1

Additional Differential Considerations

The differential diagnosis extends beyond infection: 1

• Mondor disease
• Costochondritis
• Chest wall pain
• Trauma-related pain
• Inflammatory breast cancer (rarely)

Special Population Considerations

In women over 50 years, non-lactational mastitis may indicate: 1

• Underlying duct ectasia
• Need for evaluation to exclude malignancy

Delay in recognizing inflammatory breast cancer significantly worsens mortality, making early recognition paramount 1