DESCRIPTION 
- Infection of the breast causing pain, swelling, and erythema
- Most commonly in women who are breast-feeding
- Often with systemic symptoms also:
- Incidence may be as high as 33% in lactating woman
- Onset typically 2–3 wk to months postpartum
- 75–95% occur before infant is 3 mo old
- Rare during 1st postpartum week
- More common in advanced maternal age and patients with diabetes
- Complications:
Pediatric Considerations
Can occur in full-term infants < 2 mo of age
ETIOLOGY
- Staphylococcus aureus most common
- Less common causes:
- Risk factors:
- Cleft lip or palate
- Cracked nipples
- Infant attachment issues
- Local milk stasis
- Nipple piercing
- Poor maternal nutrition
- Previous mastitis
- Primiparity
- Restriction from a tight bra
- Sore nipples
- Short frenulum in infant
- Use of a manual breast pump
- Yeast infection
[Outline]
SIGNS AND SYMPTOMS
- Fever and chills
- Temperature usually > 38.3°C (101°F)
- General malaise
- Tachycardia
- Breast pain, induration, erythema, warmth; usually unilateral
- Onset typically 2–3 wk to months postpartum while breast-feeding
- Rare during 1st postpartum week
History
- Flu-like symptoms
- Fever, malaise, and myalgia
- Breast redness, swelling
- Breast pain
- Decreased milk outflow
Physical Exam
- Breast is:
- Warm
- Tender
- Indurated
- Erythematous – often in a wedge-shaped pattern
- Usually unilateral breast involvement
- Purulent nipple discharge can occur
- Axillary lymph nodes may be enlarged
ESSENTIAL WORKUP
Physical exam with special attention to detecting abscess:
- Abscess is frequently difficult to detect, but is more common in periareolar area
- Purulent nipple discharge with palpation
Pediatric Considerations
- In neonates:
- Consider the presence of abscess formation and systemic symptoms of infection (e.g., lethargy, poor feeding, fever)
- Sepsis workup may be needed if neonates are febrile and ill appearing
- A complete blood count (CBC) with differential and blood culture need to be considered before the initiation of antibiotics
DIAGNOSIS TESTS & INTERPRETATION
Lab
Breast milk culture is usually not required
Imaging
- Consider breast US if abscess is suspected
- Mammography is not indicated acutely
DIFFERENTIAL DIAGNOSIS
- Breast engorgement:
- Transient fever < 39°C of 4–16 hr duration
- Appearing 48–72 hr postpartum
- Bilateral nonerythematous engorgement
- Carcinoma (inflammatory)
- Cyst, tumor
- Abscess formation
[Outline]
PRE-HOSPITAL
Generally no pre-hospital treatment needed
INITIAL STABILIZATION/THERAPY
No specific stabilization
ED TREATMENT/PROCEDURES
- Continue breast-feeding:
- Child and mother are colonized with the same organisms
- Milk from a breast with mastitis may be protective
- If an infant does not like the taste of milk from a breast with mastitis, then encourage the mother to pump and discard
- Massage
- Hot/cold therapy
- Improve breast-feeding technique:
- May need a lactation consultant
- Maintain good maternal hydration.
- If mild symptoms and early in disease, antibiotics may not be necessary.
- Oral antibiotics for 7–14 days:
- β-Lactamase–resistant penicillin (e.g., dicloxacillin)
- 1st-generation cephalosporin (e.g., cefalexin)
- Clindamycin or trimethoprim/sulfamethoxazole (TMP/SMX) or erythromycin if penicillin allergic
- Surgical consultation if evidence of abscess
- If considering methicillin-resistant S. aureus (MRSA), treat according to local susceptibility patterns:
ALERT
Vertical transmission of HIV (mother to infant) may be increased in mothers with mastitis.
MEDICATION
- Amoxicillin/clavulanate: 875 mg PO q12h
- Cephalexin: 500 mg PO q6h for 10 days
- Clindamycin: 300 mg PO q6h for 10 days
- Dicloxacillin: 500 mg PO q6h for 10 days (1st-line treatment)
- Erythromycin: 500 mg PO q6h for 10 days
- Mupirocin 2% ointment TID
- TMP/SMX: 160/800 mg PO q12h:
- Avoid in compromised infants and healthy infants < 2 mo old
- If MRSA positive: Vancomycin 1 g IV q12h
First Line
Dicloxacillin
Second Line
- Amoxicillin/clavulanate
- Cephalexin
- Erythromycin
- TMP/SMX
[Outline]
DISPOSITION
Admission Criteria
- Incision and drainage under general anesthesia may be necessary and require admission
- Immunocompromised or evidence of septicemia
- Patients with diabetes may account for 1/3 of mastitis cases
- Neonatal mastitis generally requires admission
Discharge Criteria
- Most patients may be managed in outpatient setting
- Most symptoms resolve within 48 hr of therapy
- In simple mastitis, breast-feeding may be continued, including using affected breast:
- Gently massage to enhance drainage
- Counsel that this will not harm baby
- Breast support, warm compresses, and analgesia for comfort
- In frank abscess, discontinue breast-feeding until purulent discharge resolves
- Follow-up should be arranged to exclude diagnosis of inflammatory carcinoma
FOLLOW-UP RECOMMENDATIONS
- Patients should follow up with primary care physician
- Lactation consultant may be helpful
[Outline]
- Dixon JM, Khan LR. Treatment of breast infection. BMJ. 2011;342:d396.
- Jahanfar S, Ng CJ, Teng CL. Antibiotics for mastitis in breastfeeding women. Cochrane Database Syst Rev. 2009;(1):CD005458.
- Schoenfeld EM, McKay MP. Mastitis and methicillin-resistant Staphylococcus aureus (MRSA): The calm before the storm? J Emerg Med. 2010;(38):e31–e34.
- Spencer JP. Management of mastitis in breastfeeding women. Am Fam Physician. 2008;78:727–731.
- Stafford I, Hernandez J, Laibl V, et al. Community acquired methicillin-resistant Staphylococcus aureus among patients with puerperal mastitis requiring hospitalization. Obstet Gynecol. 2008;112:533–537.
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