Breast abscess and Mastitis and Fat Necrosis

Related Subjects: | Assessment of the Causes of Breast tenderness/pain (Mastalgia) | BRCA genes (Familial Breast Cancer) | Breast Anatomy and Examination (OSCE) | Breast Cancer | Breast Fibroadenoma | Breast Lumps: Clinical Approach and Considerations | Breast abscess and Mastitis and Fat Necrosis

🤱 Mastitis = inflammation of breast tissue (with or without infection). 💥 Breast abscess = a localised collection of pus, usually a complication of mastitis and rarely resolves with antibiotics alone. 🎯 Exam focus: treat pain + maintain drainage (continue feeding/expressing) + give antibiotics when indicated + use ultrasound to exclude abscess + safety-net for inflammatory breast cancer.

📖 Quick Definitions (high-yield)

• 🔥 Mastitis: inflammation of breast tissue; can be lactational (commonest) or non-lactational.
• 🧫 Infective mastitis: milk stasis + bacterial entry (often via cracked nipples) → cellulitis/infection.
• 🟡 Breast abscess: painful, fluctuant infected collection; needs drainage + antibiotics.
• 🧈 Fat necrosis: ischaemic necrosis of fat lobules (often after trauma/surgery); can mimic cancer clinically and on imaging.

🧠 Pathophysiology (why it happens)

• 🍼 Milk stasis (poor latch, infrequent feeds, pressure from tight bra, sudden weaning) → duct obstruction → local inflammation.
• 🦠 Bacterial entry (skin flora via nipple cracks) + stagnant milk → infection; S. aureus common; consider MRSA if risk factors.
• 🚬 Non-lactational/periductal disease: smoking-associated duct damage/duct ectasia → recurrent subareolar inflammation and abscess tendency.

⚡ Buzzwords (your original content, tightened)

• Risk factors: breastfeeding, cracked nipples, smoking, duct ectasia, Staphylococcus aureus.
• Presentation (mastitis): swelling, tenderness, erythema, induration; may feel “wedge-shaped” inflammation; systemic malaise/fever.
• Presentation (abscess): localised painful lump + warmth/erythema + fluctuance ± fever.

🚩 Red Flags & Safety Net (don’t miss cancer)

⚠️ Inflammatory breast cancer can mimic mastitis. If symptoms are not settling as expected, or there is peau d’orange, rapid progression, or suspicious nodes → urgent breast clinic referral.

🔬 Investigations (OSCE-structured)

• 🧪 Bloods (only if systemically unwell): FBC (↑WCC), CRP; blood cultures if septic features.
• 🖼️ Breast ultrasound (key test): if abscess suspected, severe symptoms, atypical course, or poor response to treatment.
• 🧫 Milk/pus culture: if abscess, recurrent disease, MRSA risk, or failure of first-line antibiotics.
• 📸 Consider mammography/clinic follow-up: especially in non-lactational presentations or older patients once acute inflammation settles.

💊 Management - Mastitis (exam-ready, stepwise)

✅ Three pillars: 1) Pain control 2) Drain the breast (keep feeding/expressing) 3) Antibiotics when infection likely or symptoms persist/worsen.

1. 😌 Analgesia & supportive care
   • 💊 Paracetamol ± ibuprofen (if no contraindications)
   • 🌡️ Fluids, rest, treat fever
   • 🧴 Warm compress pre-feed and gentle massage toward nipple (avoid overly aggressive massage)
2. 🍼 Maintain milk drainage (do not “rest” the breast)
   • ✅ Continue breastfeeding on the affected side if possible (or express/pump if too painful)
   • 🔁 Encourage frequent emptying (regular feeds/expressing through the day)
   • 👶 Check latch/positioning; address cracked nipples (reduces recurrence)
3. 🦠 Antibiotics (when indicated)
   • Start antibiotics if: systemic features, obvious infection/cellulitis, or symptoms persist/worsen after ~12–24 hours of effective drainage/support.
   • First-line (lactating mastitis): Flucloxacillin 500 mg QDS for 10–14 days (typical UK guidance; follow local policy).
   • Penicillin allergy: A macrolide option (e.g., erythromycin/clarithromycin) may be used (follow local policy).
   • MRSA risk / failure to respond: culture and tailor; consider local guideline/ID advice.

🧠 Course length note: Many UK pathways use 10–14 days when antibiotics are needed. Reassess clinically at 24–48h and follow local antimicrobial policy.

💥 Breast Abscess (keep it practical)

• Definition: painful collection of pus in breast tissue.
• Risk factors: breastfeeding, smoking, preceding mastitis.
• Exam clue: localised tender mass with fluctuance ± fever.

🖼️ Ultrasound features (your original content, clarified)

• 🖥️ USS often shows a hypoechoic collection with an echogenic wall/capsule (appearance varies with complexity).

🧫 Management - Abscess (what examiners want)

1. 🖼️ Confirm with ultrasound and involve breast team/surgical assessment.
2. 💉 Aspiration/drainage
   • US-guided needle aspiration is commonly preferred; incision & drainage if large/loculated, skin compromise, or failed aspiration.
   • Send pus for microscopy, culture & sensitivities (MC&S).
3. 💊 Antibiotics
   • Antibiotics alone are usually insufficient without drainage.
   • Choice depends on local policy and culture; co-amoxiclav is used in some local protocols (your original content), but always follow trust guidance.
4. 🔁 Follow-up
   • Reassess clinically; repeat aspiration may be needed.
   • Non-lactational abscesses or atypical courses often need breast clinic follow-up to exclude underlying pathology.

🧈 Fat Necrosis (cancer mimic)

• Definition: ischaemic necrosis of fat lobules.
• Risk factors: recent trauma, surgery, radiotherapy.
• Presentation: lump ± skin dimpling/tethering; may feel firm/irregular.
• Investigations:
  • 🖼️ USS may show a hyperechoic lesion (variable)
  • 📸 Mammogram can mimic carcinoma
  • 🧫 Core biopsy if diagnostic uncertainty (do not assume benign if suspicious)
• Management: analgesia and reassurance once malignancy excluded.

🧾 Differentials (kept, but made exam-friendly)

• For mastitis/abscess-like presentations: abscess, fat necrosis, cyst, fibroadenoma, duct ectasia/periductal mastitis, DCIS, invasive breast cancer.
• Always consider: “is this actually malignancy?” if non-lactational, recurrent, unilateral persistent skin change, or poor response to appropriate management.

📊 Comparison Table - Mastitis vs Breast Abscess vs Fat Necrosis

🎯 OSCE Mini-Script (60 seconds)

• 👋 Confirm postpartum/breastfeeding status, duration of symptoms, fever/systemic upset, nipple trauma, prior episodes, smoking, MRSA risks.
• 🩺 Examine: erythema pattern, tenderness, induration vs fluctuant lump, nipple cracks/discharge, axillary nodes, peau d’orange.
• ✅ Plan: analgesia + continue feeding/expressing + antibiotics if indicated; request ultrasound if abscess suspected or poor response; safety-net and refer urgently if not improving or cancer features.

📚 References (UK + core)

• NICE CKS: Mastitis and breast abscess (definition and management summaries).
• NHS Scotland Right Decisions: lactational mastitis antibiotic options/duration; continue breastfeeding.
• BMJ Best Practice: breast abscess requires drainage + antibiotics.
• WHO: Mastitis - causes and management (core lactational principles).
• Cancer Research UK: inflammatory breast cancer symptoms (red flag mimic).