A breast abscess is an encapsulated accumulation of pus within the breast tissue that most commonly results from puerperal mastitis. Nonpuerperal abscesses are uncommon and may be caused by trauma. Breast abscesses typically manifest as a tender, erythematous breast mass with or without systemic signs of infection, such as fever. The diagnosis is primarily clinical, but imaging and aspiration are often required for confirmation and to guide management. Treatment involves drainage, antibiotics, and analgesia.
- Commonly a complication of mastitis, especially puerperal mastitis 
- Nonpuerperal abscesses (uncommon) may be caused by trauma and are associated with obesity, cigarette smoking, and immunosuppression. 
- Polymicrobial infections with aerobic and anaerobic bacteria are common; see “Infectious mastitis” for details.
Although abscess is often diagnosed clinically, imaging and aspiration are used to confirm the diagnosis and guide management. 
Breast ultrasound 
- Indications: initial imaging modality for suspected breast abscess 
- Irregular, hypoechoic fluid-filled lesions with an echogenic rim and posterior acoustic enhancement
- No vascularity within the fluid collection on Doppler.
- Inflammatory axillary lymphadenopathy may be present.
- Nonpuerperal abscesses (after the acute phase) 
- Prolonged symptoms in a lactating woman
- Findings: asymmetrical mass or architectural distortion with skin thickening
Fine needle aspiration
- Can be diagnostic and therapeutic 
- Aspiration of purulent fluid confirms the diagnosis. 
- Aspirate should be sent for cultures.
Treatment typically involves drainage, antibiotics, and adequate pain management. Surgical excision may be considered for chronic abscesses or fistulas. 
Abscess drainage 
- Percutaneous drainage; : first-line for abscesses with intact overlying skin 
- Incision and drainage; : Consider for multiloculated or large abscesses, necrosis of overlying skin, or failure of percutaenous drainage. 
Antibiotic treatment 
- See “Empiric antibiotics for breast infections.”
- Tailor therapy based on cultures.
Patients with puerperal abscesses can continue to breastfeed. Patients who have undergone an incision and drainage may consider using a breast pump.