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Breast Abscess

Basics

  • Localized infected fluid collection in breast parenchyma
  • Associated mastitis (infectious or noninfectious)
  • Synonyms: mammary abscess, peripheral breast abscess, subareolar abscess, puerperal abscess
  • Systems affected: skin/exocrine, immune
  • Predominantly in females, reproductive and perimenopausal age

Epidemiology

  • Most common benign breast problem during pregnancy/puerperium
  • 3-11% of women with mastitis develop abscess
  • 90% of nonlactational abscesses are subareolar
  • Higher risk: African American women, diabetics, smokers, obese women

Etiology and Pathophysiology

Puerperal abscess

  • Associated with hyperlactation, milk stasis, duct obstruction, dysbiosis of milk microbiome
  • Bacteria enter through nipple fissures (often infant oral flora)
  • Inadequate mastitis treatment or milk stasis contributes

Subareolar abscess

  • Linked to squamous metaplasia, keratin plugs, duct ectasia, fistula formation

Microbiology

  • Most common: Staphylococcus aureus (including MRSA)
  • Others: coagulase-negative Staphylococci, Streptococcus spp., E. coli, Enterobacteriaceae, anaerobes

Risk Factors

  • Smoking, maternal age >30 years, primiparity, post-term pregnancy
  • Diabetes, obesity, nipple piercing
  • Milk stasis due to infrequent feeding, poor latch, nipple damage, oversupply, stress
  • Medical: steroids, breast implants, lumpectomy with radiation, inadequate mastitis antibiotics

Prevention

  • Frequent breast emptying on demand or pumping
  • Early mastitis treatment (antibiotics, milk expression, compresses)
  • Smoking cessation

Diagnosis

History

  • Tender unilateral breast lump
  • Breastfeeding, weaning, return to work
  • Systemic malaise, fever, nipple drainage
  • History of mastitis, diabetes, smoking

Physical Exam

  • Fever, tachycardia (may be absent)
  • Erythema, tenderness, induration, palpable mass (fluctuant)
  • Local edema, skin/nipple retraction, lymphadenopathy
  • Peripheral abscesses in puerperal; subareolar in nonlactational

Differential Diagnosis

  • Engorgement, plugged duct, mastitis
  • Galactocele, fibrocystic changes, fat necrosis
  • Granulomatous mastitis, tuberculosis, sarcoidosis
  • Syphilis, foreign body reaction, duct ectasia
  • Breast carcinoma (inflammatory, squamous)

Diagnostic Tests

  • Ultrasound: detects fluid collection, loculation
  • Elevated WBC, ESR
  • Culture of breast milk or aspirate for pathogen ID
  • Mammography generally deferred acutely; used to exclude malignancy
  • Aspiration (± US guided) diagnostic and therapeutic
  • Cytology in nonlactating patients to rule out malignancy

Treatment

General Measures

  • Cold/warm compresses for pain
  • Continue breastfeeding or milk expression to drain breast
  • Antibiotics alone ineffective without drainage

Medications

  • Antibiotics tailored to culture/sensitivity
  • First line (nonsevere, no MRSA risk): dicloxacillin or cephalexin 500 mg QID for 10-14 days
  • MRSA risk: clindamycin or TMP-SMX
  • Infectious disease consult if poor response to antibiotics + drainage
  • NSAIDs for analgesia and antipyresis
  • Supportive care: rest, hydration, nutrition

Procedures

  • Ultrasound-guided needle aspiration for abscess <3 cm (may require serial aspirations)
  • Percutaneous catheter drainage for abscess >3 cm
  • Surgical incision and drainage for abscess >5 cm, recurrent, or chronic
  • Biopsy nonpuerperal abscesses and remove fistulous tracts if present

Additional Therapies

  • Lecithin supplements, probiotics
  • Acupuncture and lymphatic massage may aid engorgement
  • Cabbage leaves may reduce inflammation and milk production

Admission Criteria

  • Generally outpatient unless septic, immunocompromised, or unstable
  • Hospital-grade breast pump recommended during admission

Ongoing Care

  • Continued effective milk removal to prevent recurrence
  • Avoid abrupt weaning

Follow-Up

  • Close outpatient follow-up until resolution
  • Ensure complete resolution and exclude malignancy

Patient Education

  • Emphasize wound care, rest, and ongoing milk expression
  • Avoid infant mouth contact with affected tissue if feeding impossible

Prognosis

  • Abscess heals inside-out in ~8-10 days
  • Subareolar abscesses frequently recur; may require surgery

Complications

  • Mammary duct or milk fistula
  • Poor cosmetic outcome
  • Early cessation of breastfeeding

Clinical Pearls

  • Up to 11% of puerperal mastitis progresses to abscess if inadequately treated
  • Ultrasound-guided aspiration preferred over incision & drainage for better cosmesis and faster recovery
  • If abscess <5 cm, surgical I&D recommended
  • Continue breast emptying (feeding/pumping) during treatment