A breast abscess is a localized collection of infected fluid within breast tissue, most commonly arising as a complication of infectious mastitis. Approximately 3% of women with mastitis develop a breast abscess. [1] The most common causative organism is Staphylococcus aureus, with MRSA playing an increasingly important role. [1-2] Breast abscesses are classified as lactational (puerperal) or non-lactational (non-puerperal), with management nuances for each.
1. History
- Lactation status: Currently breastfeeding? Postpartum timing? Duration of lactation?
- Symptom onset and progression: Acute onset of breast pain, swelling, erythema — did it begin as mastitis that failed to resolve?
- Prior treatment: Previous antibiotics? Duration and type? Any prior drainage attempts?
- Breast-specific: Nipple trauma/cracking, recent breast surgery, nipple piercing, prior breast abscess episodes
- Feeding history: Latch difficulties, missed feedings, use of breast pump, history of non-professional breast massage (a risk factor for abscess progression) [2]
- Systemic symptoms: Fever, chills, malaise, body aches, flu-like symptoms [3]
- Important negatives: Nipple discharge (bloody?), skin dimpling, peau d'orange, weight loss (to screen for malignancy mimics)
2. Alarm Features
- Sepsis/SIRS: Temp >38°C or <36°C, HR >90, RR >24, WBC >12,000 or <4,000 — indicates need for IV antibiotics and possible admission [4]
- Failure to improve after 48 hours of appropriate antibiotics — raises concern for resistant organism, undrained collection, or alternative diagnosis [3]
- Peau d'orange, skin thickening, diffuse erythema involving ≥1/3 of the breast — must consider inflammatory breast cancer (IBC), especially in non-lactating patients [5-6]
- Non-lactating patient with breast erythema and no clear infectious source — higher suspicion for malignancy [7]
- Rapidly expanding cellulitis, crepitus, or dusky skin — consider necrotizing soft tissue infection
- Recurrent subareolar abscess — suggests periductal mastitis with squamous metaplasia of lactiferous ducts (PDM-SMOLD) or fistula formation [8-9]
3. Medications
First-line antibiotics (lactational abscess)
- Dicloxacillin 500 mg QID or cephalexin 500 mg QID — recommended first-line per ASBrS 2025 guidelines [8]
- Penicillin allergy: cephalexin (if non-anaphylactic) or clindamycin [1]
- Phlegmon present: antibiotics for at least 10 days [8]
Non-lactational abscess
- Amoxicillin-clavulanate (covers anaerobes common in periductal infections) [9]
- Penicillin allergy: erythromycin + metronidazole [9]
MRSA coverage (when suspected)
- TMP-SMX or doxycycline for outpatient; vancomycin IV for inpatient [1]
- Clindamycin is an option but resistance rates are high (up to 80% in MRSA isolates) [2]
Medications to avoid
- Empiric quinolones (poor MRSA coverage, resistance common) [1]
- Macrolides alone (high MRSA resistance) [1]
Supportive
- NSAIDs (ibuprofen) for pain and inflammation
- Acetaminophen as adjunct analgesic
4. Diet
- Hydration: Adequate fluid intake, especially in lactating patients
- Breastfeeding: It is safe to continue breastfeeding from the affected breast, even with an abscess or after lidocaine injection for drainage procedures [8]
- Counsel against "emptying" the breast with aggressive massage or excessive pumping — this is contraindicated per current guidelines [8]
- No specific dietary restrictions; ensure adequate caloric intake for lactating mothers
5. Review of Systems
- Constitutional: Fever, chills, rigors, fatigue, malaise (systemic infection)
- Breast: Pain, swelling, erythema, warmth, nipple discharge, skin changes
- Skin: Rash, peau d'orange, skin ulceration, nipple excoriation (malignancy red flags)
- Lymphatic: Axillary or supraclavicular lymphadenopathy
- MSK/General: Weight loss, bone pain (if concern for metastatic disease)
- OB/GYN: Pregnancy status, menstrual history, lactation history
6. Collateral History and Family History
- Collateral: Lactation consultant involvement, prior breast imaging results, recent healthcare exposures (MRSA risk)
- Family history: Breast cancer (especially premenopausal), BRCA mutations — relevant when considering malignancy in the differential
- Social context: Smoking status (major risk factor for periductal mastitis and recurrent subareolar abscess), IV drug use, immunosuppressive medications [9]
7. Risk Factors
Lactational abscess
- Age >30 years, primiparity [1]
- Gestational age ≥41 weeks at delivery [1]
- Cracked/damaged nipples, poor latch, milk stasis
- Delayed treatment of mastitis (onset ≥2 days before presentation) [2]
- Non-professional breast massage [2]
- S. aureus or MRSA colonization [2]
Non-lactational abscess
- Smoking (strongest risk factor for periductal mastitis) [9]
- Diabetes mellitus, steroid use, immunosuppression [9]
- Nipple piercing
- Obesity
- African American race (higher risk for IBC, which can mimic abscess) [6]
8. Differential Diagnosis
- Inflammatory breast cancer — the cannot-miss diagnosis; suspect if erythema involves ≥1/3 of breast, peau d'orange, no fever, non-lactating, or failure to respond to antibiotics within 7–10 days [3][5-6]
- Phlegmon — firm, mass-like area without fluctuance; ill-defined fluid on ultrasound; should NOT be drained; requires extended antibiotics [3]
- Galactocele — milk retention cyst; no erythema or systemic symptoms unless secondarily infected [3]
- Granulomatous mastitis — chronic, recurrent; requires core biopsy for diagnosis; often mimics abscess or cancer [8]
- Periductal mastitis (PDM-SMOLD) — recurrent subareolar abscesses, often in smokers; distinct entity requiring specific management [8-9]
- Cellulitis without abscess — diffuse erythema without fluctuance or drainable collection
- Paget disease of the nipple — nipple excoriation, scaling, ulceration [9]
- Fat necrosis — history of trauma; firm, painless mass
- Tuberculous mastitis — rare; consider in endemic areas or immunocompromised patients [10]
9. Past Medical History
- Prior breast abscess or mastitis episodes (recurrence risk)
- Prior breast surgery or biopsy
- Diabetes mellitus, HIV, immunosuppressive therapy
- Rheumatoid arthritis, granulomatous conditions
- Smoking history
- Breast implants
- Prior breast cancer or radiation therapy
10. Physical Exam
Vital signs
Breast exam
- Erythema, induration, warmth over affected area [5]
- Fluctuance — key finding suggesting drainable collection
- Skin changes: peau d'orange, dimpling, ulceration, skin breakdown (red flags for malignancy or advanced infection)
- Nipple: retraction, discharge (purulent, bloody), excoriation
- Demarcate erythema borders with skin marker for monitoring
Regional
- Axillary and supraclavicular lymphadenopathy — assess for reactive vs. suspicious nodes [9]
- Contralateral breast exam
Focused maneuvers
- Assess for crepitus (necrotizing infection)
- Assess skin thickness and attenuation (thin skin may preclude aspiration, favoring I&D) [8]
11. Lab Studies
- Routine labs are generally not needed for uncomplicated breast abscess in immunocompetent patients [3]
- Abscess fluid culture and sensitivity — send with every drainage procedure to guide antibiotic therapy [5][9]
- CBC, CRP — of limited diagnostic value (elevated in both infectious and inflammatory conditions) but useful if sepsis is suspected [3]
- Blood cultures — if SIRS criteria met or concern for bacteremia
- Milk culture — consider in high-risk patients: MRSA risk, failed antibiotics, immunocompromised, infant in NICU, recurrent/severe infection [3]
- BMP — if admission anticipated or IV antibiotics planned
- HbA1c/glucose — if diabetes suspected as contributing factor
12. Imaging
First-line: Ultrasound
- Breast ultrasound is the imaging modality of choice for diagnosing and guiding management of breast abscess [5][11-12]
- Findings: hypoechoic lesion with irregular borders, internal debris, possible septations/loculations [1]
- Distinguishes abscess (drainable) from phlegmon (not drainable) [3]
- POCUS: 94.6% sensitive, 85.4% specific for differentiating abscess from cellulitis [12]
- Useful for guiding needle aspiration and drain placement [8]
Mammography
- Not first-line for acute abscess
- Indicated if symptoms are refractory to treatment to rule out malignancy, or if patient is due for age-appropriate screening [8][11]
- No contraindication to mammography during pregnancy or lactation [11]
When imaging is unnecessary
13. Special Tests
- Point-of-care ultrasound (POCUS) — highly valuable in the ED for confirming abscess, guiding drainage, and ruling out pseudoaneurysm with color Doppler [12]
- Core needle biopsy — indicated if phlegmon does not resolve after 1 month of treatment, or if malignancy is suspected [8]
- Skin punch biopsy — if inflammatory breast cancer is suspected (peau d'orange, erythema ≥1/3 of breast, no response to antibiotics); note that a benign punch biopsy does not rule out IBC [11]
- Wound culture — aerobic and anaerobic cultures from aspirated/drained fluid
14. ECG
- Not routinely indicated for breast abscess
- Obtain if sepsis is suspected (tachycardia workup, pre-procedural assessment)
- Consider if planning procedural sedation for operative drainage
15. Assessment
Breast abscess is a localized suppurative complication of mastitis requiring source control (drainage) plus antibiotics. Key clinical decision points:
- Lactational vs. non-lactational — different microbiology and recurrence patterns
- Abscess vs. phlegmon — ultrasound differentiates; phlegmons should NOT be drained [3]
- Size matters: <3 cm → aspiration first; >3 cm → stab incision with drain placement (lactational) or aspiration attempt (non-lactational) [8][13]
- Atypical presentations (non-lactating, recurrent, non-responsive to treatment) warrant malignancy workup [3][6]
- Complications: fistula formation, recurrence, sepsis, scarring, breastfeeding cessation
16. Treatment Plan
Initial stabilization
- IV access and fluid resuscitation if septic
- Analgesia (NSAIDs ± acetaminophen; consider procedural analgesia)
Source control — tiered approach
Key procedural pearls
- No packing — current guidelines recommend against wound packing; place a gravity drain instead, remove in 3–5 days [8]
- Incision should be as small as possible and as far from the nipple-areolar complex as possible [8]
- Aspiration yields same cure rate with better cosmesis and shorter healing time compared to I&D [8]
Antibiotics
- All patients should receive concurrent antibiotics [13]
- Lactational: dicloxacillin or cephalexin 500 mg QID × 10–14 days [1][8]
- Non-lactational: amoxicillin-clavulanate 875/125 mg BID [9]
- MRSA suspected: TMP-SMX DS BID or doxycycline 100 mg BID [1]
- Adjust based on culture results
Breastfeeding
- Safe to continue from the affected breast [8]
- Avoid aggressive massage or excessive pumping [8]
17. Disposition
Discharge criteria (majority of patients)
- Hemodynamically stable, non-toxic appearing
- Successful drainage performed
- Tolerating oral antibiotics
- Reliable follow-up available
- Most breast abscesses can be managed as outpatient [15]
Admission criteria
- Sepsis or SIRS with hemodynamic instability [4]
- Failed outpatient management
- Immunocompromised patient with severe infection
- Need for IV antibiotics
- Inability to tolerate oral intake
- Need for operative drainage under sedation [8]
Observation indications
- Borderline vital signs after drainage
- Large or complex abscess requiring close monitoring
Specialist consultation triggers
- Recurrent abscess (breast surgery referral) [9][13]
- Suspected inflammatory breast cancer (urgent breast surgery/oncology) [6]
- Non-resolving phlegmon after 1 month (core biopsy needed) [8]
- Fistula formation in PDM-SMOLD [8]
- Granulomatous mastitis suspected [8]
18. Follow Up / Return Precautions
Follow-up timing
- 48–72 hours after drainage for wound check and clinical reassessment
- Repeat ultrasound if symptoms not improving to assess for residual/recurrent collection [3]
- If drain placed, return in 3–5 days for drain removal [8]
- Non-lactating patients with resolved abscess should have age-appropriate breast cancer screening once inflammation resolves [8]
Return precautions — counsel patients to return for
- Worsening pain, swelling, or erythema despite antibiotics
- New or worsening fever/chills
- Red streaking from the breast
- Inability to tolerate oral medications
- Signs of wound dehiscence or fistula formation
Patient counseling
- Breastfeeding is safe and encouraged from both breasts [8]
- Avoid aggressive breast massage or over-pumping [8]
- Complete the full antibiotic course
- Smoking cessation counseling for patients with periductal mastitis [9]
Expected recovery
- Most lactational abscesses resolve within 1–2 weeks with appropriate drainage and antibiotics
- Recurrence is low when guidelines are followed [8]
- Non-lactational and PDM-SMOLD abscesses have higher recurrence rates and may require surgical referral [8-9]
Images
References
1. Treatments for Breast Abscesses in Breastfeeding Women. — Irusen H, Rohwer AC, Steyn DW, Young T. The Cochrane Database of Systematic Reviews. 2015.
2. Risk Factors and Prognosis of Acute Lactation Mastitis Developing Into a Breast Abscess: A Retrospective Longitudinal Study in China. — Li D, Li J, Yuan Y, et al. PloS One. 2022.
3. Mastitis: Rapid Evidence Review. — Morcomb EF, Dargel CM, Anderson SA. American Family Physician. 2024.
4. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. — Stevens DL, Bisno AL, Chambers HF, et al. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2014.
5. Society of surgical oncology medical student & trainee primer for breast surgical oncology. — Marissa K. Boyle, Julia M. Selfridge, Rachel E. Sargent, et al Surgical Oncology Insight. 2025.
6. Inflammatory Breast Cancer: Early Recognition and Diagnosis Is Critical. — Hester RH, Hortobagyi GN, Lim B. American Journal of Obstetrics and Gynecology. 2021.
7. Breast Imaging of Infectious Disease. — Rashid T, Sae-Kho TM, Heuvelhorst KL, Glazebrook KN. The British Journal of Radiology. 2023.
8. American Society of Breast Surgeons, Society of Breast Imaging, and College of American Pathology 2025 Guidelines for the Management of Infectious and Inflammatory Lesions of the Breast. — Mitchell KB, Valente SA, Snider HC, et al. JAMA Surgery. 2026.
9. Practice Bulletin No. 164: Diagnosis and Management of Benign Breast Disorders. — Committee on Practice Bulletins—Gynecology Obstetrics and Gynecology. 2016.
10. Inflammatory Diseases of the Breast. — Scott DM. Best Practice & Research. Clinical Obstetrics & Gynaecology. 2022.
11. Breast Cancer Screening and Diagnosis. — Updated 2026-03-05. National Comprehensive Cancer Network.
12. Ultrasound Guidelines: Emergency, Point-of-Care, and Clinical Ultrasound Guidelines in Medicine. — American College of Emergency Physicians (2023). 2023.
13. Breast Abscess: Evidence Based Management Recommendations. — Lam E, Chan T, Wiseman SM. Expert Review of Anti-Infective Therapy. 2014.
14. Abscess Management: An Evidence-Based Review for Emergency Medicine Clinicians. — Menegas S, Moayedi S, Torres M. The Journal of Emergency Medicine. 2021.
15. Diagnosis and Management of Cellulitis and Abscess in the Emergency Department Setting: An Evidence-Based Review. — Long B, Gottlieb M. The Journal of Emergency Medicine. 2022.