Breast Abscess

Descriptive text is not available for this image BASICS

DESCRIPTION

  • Breast abscess: localized accumulation of infected fluid within the breast parenchyma
  • Mastitis: breast inflammation with or without infection; this can be associated with lactation (puerperal) or nonlactational.
  • Associated with lactation or fistulous tracts secondary to squamous epithelial neoplasm or duct occlusion
  • System(s) affected: skin/exocrine, immune
  • Synonym(s): mammary abscess; peripheral breast abscess; subareolar abscess; puerperal abscess

Pregnancy Considerations
Most commonly associated with postpartum lactation

EPIDEMIOLOGY

  • Most common benign breast problem during pregnancy and puerperal period (1)
  • Predominantly reproductive age and perimenopausal (between ages 18 and 50 years)
    • Puerperal abscess: lactational
    • Subareolar abscess: reproductive age through postmenopause (2)
      • 90% of nonlactational breast abscesses are subareolar (1).
  • Predominant sex: female
  • Higher incidence in African American, diabetic, tobacco use, or obese women

Incidence

Ranges between 3% and 11% of women with mastitis (1),(3)

Prevalence

Transient condition usually as a complication of mastitis; mastitis prevalence ranges between 1% and 10% (1).

ETIOLOGY AND PATHOPHYSIOLOGY

  • Puerperal abscesses:
    • Associated with hyperlactation and dysbiosis (disrupted milk microbiome); these can lead to ductal narrowing and inflammation and subsequently to reduced milk flow, obstruction, plugged lactiferous duct causing stasis, microbial growth, and infection (3).
    • Mammary dysbiosis is a consequence of multiple factors including genetic, breastfeeding-related, medical, and microbial (3).
    • Likely that bacteria (often from infants oral flora) gain entry through cracks/fissures in the nipple (1)
    • Insufficient treatment of mastitis
    • Unattended postpartum engorgement and other situations leading to breast milk stasis (3)
  • Subareolar abscess:
    • Associated with squamous metaplasia of the lactiferous duct epithelium, keratin plugs, ductal ectasia, and fistula formation (2)
  • Microbiology
    • Staphylococcus aureus is the most common cause of lactational abscesses (1),(2).
    • Methicillin-resistant S. aureus (MRSA) is a significant cause (1).
    • Other common causes include coagulase-negative staphylococci and Streptococcus spp. (2),(3).
    • Less common causes (1):
      • Escherichia coli, Enterobacteriaceae, Corynebacterium, and Pseudomonas
      • Anaerobes
      • May be polymicrobial

Genetics

Maternal genetics may play a role as protective and predisposing factors for mammary dysbiosis, which is associated with the pathophysiology (3).

RISK FACTORS

  • Smoking, maternal age >30 years
  • Primiparous, pregnancy ≥41 weeks’ gestation
  • Diabetes and obesity
  • African American
  • Nipple piercing
  • Milk stasis:
    • Infrequent or missed feeds
    • Poor latch, weak or uncoordinated suckling
    • Damage or irritation of the nipple, nipple inversion or retraction
    • Inefficient removal of milk (by baby or pump), oversupply of milk
    • Illness in mother or baby, rapid weaning, plugged duct
    • Pressure on the breast (i.e., tight bra, car seatbelt)
    • Maternal stress and fatigue
  • Medically related risk factors
    • Steroids
    • Breast implants
    • Lumpectomy with radiation
    • Inadequate antibiotics to treat mastitis
    • Topical antifungal medication used for mastitis

GENERAL PREVENTION

  • Frequent breast emptying with on-demand feeding and/or pumping to prevent mastitis
  • Early treatment of mastitis with milk expression, antibiotics, and compresses
  • Smoking cessation to minimize occurrence/recurrence

COMMONLY ASSOCIATED CONDITIONS

Lactation, mastitis, weaning

Descriptive text is not available for this image DIAGNOSIS

HISTORY

  • Tender breast lump, usually unilateral
  • Breastfeeding, weaning, or returning to work
  • Decreased breast milk supply on affected breast
  • Perimenopausal/postmenopausal
  • Systemic malaise (usually less than with mastitis)
  • Localized erythema, warmth, edema, pain
  • Fever, nausea, vomiting
  • Spontaneous nipple drainage
  • Prior breast infection
  • Diabetes
  • Smoking
  • Recent or recurrent mastitis

PHYSICAL EXAM

  • Fever, tachycardia (not always present)
  • Erythema of overlying skin
  • Palpable mass, sometimes fluctuant
  • Tenderness on palpation
  • Induration
  • Local edema
  • Draining pus or skin ulceration
  • Nipple and/or skin retraction
  • Regional lymphadenopathy
  • Puerperal abscesses are generally peripheral; nonlactational abscesses are more commonly found in periareolar/subareolar region.

DIFFERENTIAL DIAGNOSIS

  • Engorgement, plugged milk duct, mastitis
  • Galactocele (sometimes referred to as a milk lake)
  • Fibrocystic breasts
  • Fat necrosis
  • Tuberculosis (may be associated with HIV infection), sarcoid; granulomatous mastitis
  • Syphilis
  • Foreign body reactions (e.g., to silicone and paraffin)
  • Mammary duct ectasia
  • Carcinoma (inflammatory or primary squamous cell)

DIAGNOSTIC TESTS & INTERPRETATION

Initial Tests (lab, imaging)

  • Ultrasound helps identify fluid collection (1),(3).
  • Elevated WBC, elevated ESR
  • Culture of expressed breast milk or aspirate to identify pathogen
    • The presence of pathogenic bacteria or high bacteria count (e.g., > 103/mL) indicates mastitis; low predictive value; clinical context is needed (1)[C],(3).

Follow-Up Tests & Special Considerations

Mammogram to rule out malignancy (generally not done during acute phase)

Diagnostic Procedures/Other

  • Aspiration (+/− ultrasound guided) for culture
    • Can be diagnostic and therapeutic
    • Does not exclude malignancy
    • Cytology (particularly in nonlactating patient)
  • Mammography has limited value in the acute assessment of breast abscesses or mastitis (1)[C].

Test Interpretation

  • Abscesses on ultrasound can be hypoechoic, well-circumscribed, and/or macrolobulated (1)
    • If ultrasound is negative for pocket of fluid, consider alternative diagnoses.
    • If multiloculated on imaging, refer to breast surgical/interventional specialist.
  • Use culture sensitivities to guide antibiotic therapy when possible.

Descriptive text is not available for this image TREATMENT

GENERAL MEASURES

  • Cold and/or warm compresses for pain control (3)[C]
  • Continue to breastfeed or express milk to drain the affected breast (3)[A].
  • Drainage of abscess with antibiotics; without drainage, antibiotics are ineffective (2),(3)[A].
    • Acceptable to start antibiotics while working to get patient to drainage/aspiration

MEDICATION

First Line

  • Drainage for source control and culture; adjust antibiotics if indicated based on culture and sensitivities (2)[C].
  • First line for nonsevere and no MRSA risk factors (3)[C]:
    • Dicloxacillin or flucloxacillin 500 mg QID for 10 to 14 days
    • Cephalexin 500 mg QID for 10 to 14 days
  • If risk factors for MRSA, including past MRSA infection, recent hospitalization in the last 12 months, antibiotic use in the last 6 months, or severe β-lactam hypersensitivity (3)[C]:
    • Clindamycin 300 to 450 mg PO TID for 10 to 14 days
    • Trimethoprim-sulfamethoxazole (TMP-SMZ) 1 to 2 tabs PO BID for 10 to 14 days
  • Mothers should continue breastfeeding (3)[A].

Second Line

  • Clindamycin 300 mg QID for 10 to 14 days (3)[C]
  • TMP-SMZ DS BID for 10 to 14 days (3)[C]
    • Not recommended for mothers of children with G6PD deficiency; use with caution in mothers with premature infants or infants with hyperbilirubinemia, especially <30 days old.
  • Consult infectious disease specialist if inadequate response to antibiotic treatment plus drainage.

ISSUES FOR REFERRAL

If showing signs of hemodynamic instability, patient should be referred for inpatient stabilization and care (rare).

ADDITIONAL THERAPIES

  • NSAIDs for analgesia, anti-inflammatory effect, and/or antipyresis (3)[B]
  • Rest, adequate fluid intake, good nutrition (3)[B]
  • Application of heat to the breast just prior to feeding/milk expression may help with adequate milk flow (3)[C].
  • Cold packs applied after a feeding/milk expression can reduce pain and edema (3)[C].

SURGERY/OTHER PROCEDURES

  • Current best practice recommendation suggests:
    • Aspiration (using 18- to 21-gauge needle) with or without ultrasound guidance for abscesses <3 cm (1),(2)[B] (Serial aspirations may be necessary.)
      • Ultrasound-guided aspiration of breast abscess is preferred to incision and drainage (I&D) in most cases due to better cosmesis and faster recovery.
    • Consider ultrasound-guided percutaneous catheter placement if abscess >3 cm (2)[B].
    • Consider I&D using a no. 15 blade scalpel if abscess is >5 cm, recurrent, or chronic (2)[B].
  • Biopsy nonpuerperal abscesses to rule out malignancy; remove all fistulous tracts in nonlactating patients as well (2)[C].

COMPLEMENTARY & ALTERNATIVE MEDICINE

  • Lecithin supplementation
  • Probiotics
  • Acupuncture may help with breast engorgement and prevention of breast abscess.
  • Breast lymphatic massage may ease engorgement.
  • Judicious use of cabbage leaves applied over affected area (to decrease inflammation and milk production)

ADMISSION, INPATIENT, AND NURSING CONSIDERATIONS

  • Outpatient, unless systemically immunocompromised, septic, or requiring inpatient antibiotic treatment
  • Hospital-grade breast pump should be made available to patient from time of admission.

Descriptive text is not available for this image ONGOING CARE

  • If lactating, continue effective milk removal to prevent recurrence.
  • If planning to wean from breastfeeding, avoid abrupt discontinuation of feeding.
  • Consider smoking cessation to decrease risk of nonlactational abscess recurrence.

FOLLOW-UP RECOMMENDATIONS

Patient Monitoring

  • Ensure complete resolution to exclude malignancy.
  • Close outpatient follow-up until resolution as abscesses may require serial aspirations or drainage

DIET

No dietary patterns have been associated with breast abscess formation; however, these can affect the microbiome (3).

PATIENT EDUCATION

  • Wound care, rest, breast milk emptying
  • Continue with breastfeeding or pumping (if breastfeeding is not possible due to location of abscess; infant mouth not to come in contact with affected tissue) to prevent engorgement.

PROGNOSIS

  • Drained abscess heals from inside out (in 8 to 10 days).
  • Subareolar abscesses frequently recur, even after I&D and antibiotics; may require surgical removal of ducts

COMPLICATIONS

  • Fistula: mammary duct or milk fistula
  • Poor cosmetic outcome
  • Early cessation of breastfeeding

Authors

Kelley V. Lawrence, MD, IBCLC
Emily Valentin-Mendez, MD
Lauren A. Griffin, DO

REFERENCES

  1. Boakes E, Woods A, Johnson N, et al. Breast infection: a review of diagnosis and management practices. Eur J Breast Health. 2018;14(3):136–143.  [PMID:30123878]
  2. Lam E, Chan T, Wiseman SM. Breast abscess: evidence based management recommendations. Expert Rev Anti Infect Ther. 2014;12(7):753–762.  [PMID:24791941]
  3. Mitchell KB, Johnson HM, Rodríguez JM, et al; for the Academy of Breastfeeding Medicine. Academy of Breastfeeding Medicine Clinical Protocol #36: the mastitis spectrum, revised 2022. Breastfeed Med. 2022;17(5):360–376.  [PMID:35576513]

Descriptive text is not available for this image CODES

ICD10

  • N61 Inflammatory disorders of breast
  • O91.13 Abscess of breast associated with lactation
  • O91.12 Abscess of breast associated with the puerperium
  • O91.119 Abscess of breast associated with pregnancy, unsp trimester
  • O91.112 Abscess of breast associated w pregnancy, second trimester
  • O91.113 Abscess of breast associated with pregnancy, third trimester
  • O91.111 Abscess of breast associated with pregnancy, first trimester

SNOMED

  • 28432003 Abscess of breast (disorder)
  • 200374003 Obstetric breast abscess - delivered
  • 237438009 subareolar breast abscess (disorder)
  • 55704005 abscess of breast, associated with childbirth (disorder)

CLINICAL PEARLS

  • Up to 11% of cases of puerperal mastitis progress to abscess formation (most often due to inadequate therapy).
  • Risk factors for mastitis and breast abscess include a combination of genetic, microbial, breastfeeding, and medical factors.
  • Treat abscesses not associated with lactation with antibiotics that cover anaerobic bacteria and work up for malignancy.
  • The treatment of choice for most breast abscesses is the combination of antibiotics plus aspiration.
  • Ultrasound-guided aspiration of breast abscess is preferred to I&D in most cases due to better cosmesis and faster recovery.
  • If abscess is <5 cm, surgical I&D is recommended.
  • If lactating, continue to empty the breast (feeding, pumping, or expression of breast milk).

Last Updated: 2026

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