Basics
Description
- Breast abscess: infection of the breast bud or tissue associated with localized pus and inflammation
- Mastitis: infection of the breast tissue observed primarily during lactation
Epidemiology
- 5-11% of women with breastfeeding mastitis develop a breast abscess.
- Affects primarily infants (peak age 1-6 weeks) and adolescents
- Bilateral abscesses, seen among neonates, are rare.
- Male-to-female ratio is 1:2 in neonates.
Risk Factors
- In lactating teens, primiparity
- Gestational age >40 weeks
- Mastitis
- Obesity, black race, tobacco use
General Prevention
- Avoid breast manipulation (including piercing).
- In lactating teens, establish good breastfeeding techniques.
- Recognize and treat mastitis early.
Pathophysiology
- Newborns
- Trauma, breast hypertrophy from maternal estrogen, or compromised host defenses enable spread of bacteria that often colonize the nasopharynx and umbilicus.
- The bacteria and/or its toxin, in turn, cause(s) subcutaneous destruction and loculated pus formation.
- Adolescents/adults: Trauma (e.g., sexual manipulation, nipple rings, tight-fitting bras, incorrect latching during breastfeeding), contiguous spread of a local infection (e.g., mastitis, acne), or underlying structural abnormalities (e.g., mammary duct ectasia, epidermal cysts) cause breast tissue edema and destruction by bacteria and/or its toxin.
- When mastitis is associated with breastfeeding, the inflammation inhibits milk release. The stasis of milk, in turn, may allow for bacterial proliferation.
Etiology
- Newborn infection: Staphylococcus aureus (most common), group A or B Streptococcus, Bacteroides species, and gram-negative enteric bacteria, including Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Salmonella species
- Adolescent/adult infection: S. aureus (most common) with up to 19% being methicillin-resistant, E. coli, P. aeruginosa, Mycobacterium tuberculosis, Neisseria gonorrhoeae, and Treponema pallidum are infrequent pathogens.
Diagnosis
History
- Ask about history of breast trauma or manipulation, concomitant illness or infections, and patient's immunologic status.
- Constitutional symptoms including irritability and lethargy usually are absent unless the infection involves deeper tissue or the bloodstream (1/3 of cases).
- Low-grade fever
- Salmonella infections generally present with GI symptoms.
Physical Exam
- Firm, tender breast mass with overlying erythema and warmth. Fluctuant mass may be present.
- Regional adenopathy
- Purulent nipple discharge (rare)
- Necrotizing fasciitis is distinguished from breast abscess by pain out of proportion to the cutaneous signs, crepitus, or presence of straw-colored bullae.
Diagnostic Tests & Interpretation
Lab
- Gram stain and culture of nipple discharge, needle aspirate, and/or surgical incision and drainage help(s) guide therapeutic decisions if a fluctuant mass or discharge is present.
- Blood culture
- Useful in neonates
- Consider full sepsis workup if patient is febrile and toxic-appearing, or < 28 days old.
- CBC: Leukocytosis (>15,000 cells/mm3) is present in 1/2-2/3 of patients.
- Surveillance cultures of nasopharynx and umbilicus should be considered in neonates to rule out colonization with S. aureus.
Imaging
Ultrasound may be useful if fluctuant mass is suspected or if poor response to antimicrobial therapy.
Diagnostic Procedures/Other
If fluctuant, needle biopsy may be diagnostic and therapeutic.
Differential Diagnosis
- Physiologic conditions:
- Breast engorgement (usually bilateral; absence of fever, erythema and tenderness)
- Mastodynia (painful breast engorgement; associated with ovulatory cycles; cyclic pattern)
- Infectious: cellulitis including mastitis (absence of a loculated breast mass)
- Tumors (rare):
- Fibroadenomas
- Rhabdomyosarcoma
- Non-Hodgkin lymphoma
- Fibrocystic disease
- Intraductal papilloma
- Cystosarcoma phyllodes
- Hemangioma
- Trauma:
- Contusion (firm, tender, poorly defined mass)
- Hematoma (sharply defined mass with ecchymosis)
- Fat necrosis (firm, nontender, circumscribed, mobile mass)
- Miscellaneous: Mondor disease (thrombophlebitis of the subcutaneous veins in the breast)
- Typically seen in adults
- Presents with tenderness and pain
- Associated with trauma
- Spontaneously resolves
- Vascular malformation
Alert
- Neonatal infections require prompt recognition, intervention, and identification of other involved sites to avoid widespread infection and poor outcome.
- Unrecognized fluctuant mass and its subsequent drainage will delay therapeutic response.
- Incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is increasing in many regions of the country.
Treatment
Medication
- Neonatal infection (specific dosage interval based on degree of prematurity)
- Parenteral β-lactamase-resistant antistaphylococcal antibiotics (e.g., nafcillin 75-100 mg/kg/24 h) or cefotaxime 100-200 mg/kg/24 h)
- Aminoglycosides (e.g., gentamicin) should be included if the infant appears ill or if the Gram stain reveals gram-negative bacilli.
- Consider vancomycin (40 mg/kg/24 h) if MRSA suspected in neonate older than 1 month of age.
- Adolescent infection
- Parenteral antistaphylococcal antibiotics (e.g., nafcillin 50-100 mg/kg/24 h; maximum 12 g/24 h)
- Consider amoxicillin-clavulanic acid orally (45 mg/kg/24 h or 875 mg b.i.d.) or clindamycin (450-1,800 mg/24 h orally with max dose 1.8 g/24 h; 1,200-1,800 mg/24 h parenterally with max dose 4.8 g/24 h) in patients with penicillin allergies and those who are well-appearing and without systemic symptoms.
- Consider adding aminoglycosides in situations as described earlier.
- Consider vancomycin, clindamycin, or trimethoprim-sulfamethoxazole if MRSA suspected.
- Duration
- Usually for 10-14 days
- Length of parenteral treatment is based on isolate and the clinical response. Oral agents may be used after a few days if a good clinical response occurs.
Additional Therapies
General Measures
- Warm compresses
- Nonsteroidal anti-inflammatory agents (NSAIDs) help control the inflammation and pain in older children.
- Continuation of breast milk expression helps prevent engorgement and further milk stasis.
Issues for Referral
Consider referral to an infectious disease specialist if recurrent.
Surgery/Other Procedures
- Incision and drainage if a fluctuant mass is present
- Surgical exploration is necessary if necrotizing fasciitis is suspected.
Inpatient Considerations
Admission Criteria
- Ill appearance
- Neonates
- Inability to tolerate oral medications
- Concern for medication nonadherence
Ongoing Care
Follow-up Recommendations
Clinical improvement should be evident after 48 hours of parenteral antibiotics.
Alert
Signs to watch for are the following:
- A poor or delayed clinical response to antibiotic therapy suggests a resistant organism, an unusual pathogen, or a different diagnosis.
- An evolving fluctuant mass warrants surgical intervention.
- Reaccumulation of fluctuant mass
- Toxic appearance, prolonged fever, purulent discharge, or progressive erythema postoperatively
- Crepitus associated with excessive pain and/or straw-colored bullae suggests necrotizing fasciitis.
Patient Education
- Continue breastfeeding.
- Establish good breastfeeding techniques.
Prognosis
- Most children recover without any sequelae.
- Neonates are more likely to have bilateral abscesses (<5% cases).
- Neonates have higher morbidity and complications.
Complications
- Cellulitis (most common; 5-10%)
- Abscess rupture with disseminated infection (e.g., bacteremia, pneumonia)
- Septicemia
- Toxin syndromes (e.g., toxic shock syndrome)
- Necrotizing fasciitis
- Scar formation from mammary gland destruction (associated with a reduced breast size after puberty)
- Mammary duct fistula
Additional Reading
- Barbosa-Cesnik C, Schwartz K, Foxman B. Lactation mastitis. JAMA. 2003;289(13):1609-1612. [View Abstract]
- Bharat A, Gao F, Aft RL, et al. Predictors of primary breast abscesses and recurrence. World J Surg. 2009;33(12):2582-2586. [View Abstract]
- Fortunov RM, Hulten KG, Hammerman WA, et al. Community-acquired Staphylococcus aureus infections in term and near-term previously healthy neonates. Pediatrics. 2006;118(3):874-881. [View Abstract]
- Moazzez A, Kelso RL, Towfigh S, et al. Breast abscess bacteriologic features in the era of community-acquired methicillin-resistant Staphylococcus aureus epidemics. Arch Surg. 2007;142(9):881-884. [View Abstract]
- Strickler T, Navratil F, Foster I, et al. Nonpuerperal mastitis in adolescents. J Ped. 2006;148(2):278-281. [View Abstract]
- Stricker T, Navratil F, Sennhauser FH. Mastitis in early infancy. Acta Paediatr. 2005;94(2):166-169. [View Abstract]
Codes
ICD09
- 611.0 Inflammatory disease of breast
- 771.5 Neonatal infective mastitis
- 675.20 Nonpurulent mastitis associated with childbirth, unspecified as to episode of care or not applicable
ICD10
- N61 Inflammatory disorders of breast
- P39.0 Neonatal infective mastitis
- O91.219 Nonpurulent mastitis associated w pregnancy, unsp trimester
SNOMED
- 28432003 Abscess of breast (disorder)
- 276679003 Neonatal breast abscess (disorder)
- 45198002 Mastitis (disorder)
- 700038005 Mastitis associated with lactation (disorder)
FAQ
- Q: How can you differentiate a breast abscess from mastitis?
- A: Although both illnesses involve signs of inflammation (i.e., warmth, erythema, swelling, tenderness), a breast abscess is distinguished from mastitis in that the former presents as a firm, well-defined mass (with or without fluctuant material).
- Q: Should a mother discontinue breastfeeding if she has a breast abscess?
- A: To avoid milk stasis, breastfeeding should be continued unless impeded by a surgical incision site or the overall clinical condition of the mother.
- Q: What is the role of homeopathic remedies (e.g., belladonna, Phytolacca) in the treatment of mastitis and breast abscess?
- A: Currently, there is insufficient scientific evidence to support their routine use.
- Q: Are anaerobic organisms common pathogens for breast abscesses?
- A: No. Although anaerobic pathogens are isolated in up to 40% of infections, their role is controversial, and therapy directed at them is unnecessary.