Mastitis (Lactational)
Summary
Lactational Mastitis is an inflammatory condition of the breast, usually associated with lactation. It represents a continuum from non-infectious milk stasis (blocked duct) to infectious mastitis (bacterial invasion) and finally breast abscess. The cardinal rule of management is "Don't Stop Feeding". Effective milk removal is the primary treatment for all stages. [1,2]
Clinical Pearls
The "Fluclox" Rule: The causative organism is almost always Staphylococcus aureus (from skin/nasopharynx). Therefore, the antibiotic of choice is always a penicillinase-resistant penicillin (Flucloxacillin). Amoxicillin is useless.
Needle vs Knife: If an abscess forms, the Gold Standard is Ultrasound-Guided Needle Aspiration (often repeated), NOT Incision and Drainage (I&D). I&D leaves a wound, scarring, and interrupts breastfeeding. Aspiration allows feeding to continue.
Inflammatory Cancer Mimic: If "mastitis" does not resolve after a course of antibiotics, you MUST exclude Inflammatory Breast Cancer. Refer for imaging/biopsy.
Demographics
- Incidence: 20% of breastfeeding women.
- Timing: Most common in weeks 2-4 postpartum.
- Recurrence: 5-10%.
Risk Factors
- Nipple Trauma: Cracks/fissures (portal of entry).
- Ineffective Removal: Poor attachment (tongue tie?), missed feeds, hurried feeds.
- Pressure: Tight bra, car seatbelt, prone sleeping.
- Maternal: Stress, fatigue, hyperlactation.
The Continuum
- Milk Stasis: Failure to drain a lobule. Intraluminal pressure rises.
- Inflammation (Non-infective): Leaking of milk into perilobular tissue. Milk proteins induce an immune response (Cytokines -> Fever/Pain).
- Infection: Stagnant milk behaves as culture medium. Bacteria (Staph aureus, Staph albus, Streptococci) enter via nipple fissures or retrograde spread.
- Abscess: Wall-off collection of pus (late complication).
Symptoms
Signs
- Inspection: Redness, shiny skin, nipple damage.
- Palpation: Define the area of induration.
- Fluctuation: A "bouncy" sensation in the centre of the lump -> Abscess.
- Axilla: Tender lymphadenopathy.
Diagnosis
- Typically Clinical. No labs needed for uncomplicated mastitis.
Microbiology
- Breast Milk Culture: Indicated if:
- Recurrent mastitis.
- Not responding to first-line antibiotics (checking for MRSA).
- Hospital acquired (NICU involves).
- Technique: Clean nipple, hand express mid-stream sample.
Imaging
- Ultrasound: Indicated if a mass persists or abscess suspected.
Management Algorithm
BREAST PAIN + REDNESS + FEVER
↓
ASSESS FOR ABSCESS (Fluctuation?)
┌─────────┴─────────┐
NO YES
↓ ↓
MASTITIS MGMT REFER SURGERY
(See below) (US Aspiration)
↓
1. MILK REMOVAL (The Priority)
- Continue breastfeeding
- Feed from affected side first
- Check attachment / latch
- Hand express if too painful
↓
2. SUPPORTIVE
- NSAIDs (Ibuprofen)
- Cold packs (post-feed)
- Warm packs (pre-feed)
↓
3. ANTIBIOTICS?
- Indicated if: Fever >24h,
Systemic sepsis, Nipple fissure.
- **Flucloxacillin** 500mg QDS
(Erythromycin if allergic)
Antibiotic Choice
- First Line: Flucloxacillin (UK/Aus) or Dicloxacillin (USA).
- Penicillin Allergy: Erythromycin, Clarithromycin, or Cephalexin.
- Duration: 10-14 days (shorter courses risk relapse).
- Safety: Safe in breastfeeding. Monitor infant for loose stools or thrush.
Abscess Management
- Primary: Needle Aspiration under US guidance.
- Refractory: Surgical incision and drainage (Last resort).
- Cessation of Breastfeeding: The commonest specific "complication".
- Breast Abscess: 3-10% of mastitis cases.
- Candida Infection: Post-antibiotics. Burning pain out of proportion to signs.
- High success rate with prompt treatment.
- Recurrence suggests an ongoing mechanical issue (poor latch) which must be addressed by lactation consulting.
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| Mastitis Protocol | ABM (Academy Breastfeeding Medicine) | Protocol #4: Antibiotic stewardship and aspiration of abscesses. |
| Mastitis | NICE CKS | Flucloxacillin first line. |
Landmark Evidence
1. Jahanfar et al (Cochrane 2013)
- Review confirmed that antibiotics are effective for infectious mastitis but emphasized that milk removal is the prerequisite for cure.
What is Mastitis?
It is a blockage of the milk ducts that has become inflamed and often infected with skin bacteria. It causes a painful, red, swollen area on the breast and makes you feel like you have the flu.
Should I stop feeding?
Absolutely not. This is the biggest myth. The milk is "safe" for the baby (stomach acid kills the bacteria). More importantly, the only way to clear the blockage and infection is to keep the milk flowing. If you stop, the milk stagnates and turns into an abscess.
How to feed?
- Heat: Warm flannel before the feed to help flow.
- Drain: Feed from the sore side first (when the baby sucks hardest).
- Massage: Gently stroking the lump towards the nipple while the baby feeds helps flush the blockage.
Medicine
We use common antibiotics (like Flucloxacillin) which are very safe for the baby. You must finish the whole course to stop it coming back.
Primary Sources
- Amir LH, et al. ABM Clinical Protocol #4: Mastitis, Revised 2014. Breastfeed Med. 2014.
- Jahanfar S, et al. Antibiotics for mastitis in breastfeeding women. Cochrane Database Syst Rev. 2013.
- NICE CKS. Mastitis and Breast Abscess. 2022.
Common Exam Questions
- Management: "First line treatment?"
- Answer: Continued breastfeeding / Milk removal.
- Therapeutics: "Antibiotic of choice?"
- Answer: Flucloxacillin (covers Staph aureus).
- Complication: "Fluctuant mass?"
- Answer: Breast Abscess -> Needle Aspiration.
- Differential: "Painful, burning nipples, shooting pain?"
- Answer: Breast Thrush (Candidiasis).
Viva Points
- Why needle aspiration over incision?: Incision cuts the milk ducts (risk of fistula) and leaves a painful wound near the nipple, making feeding impossible. Aspiration is just a needle prick.
- Flucloxacillin in Lactation: Trace amounts enter milk. Not harmful. Theoretical risk of sensitizing baby to penicillin is negligible.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.