Neonatal mastitis

See "Mastitis" for Adolescents or Adults

Background

• Uncommon soft-tissue infection of the breast tissue in children <2mo of age
• More common in females than in males
• More commonly unilateral than bilateral
• Reported confirmed sources have included MSSA and MRSA, and rarely acetinobacter , e. coli, and proteus mirabilis
• Reported sequelae have included brain abscess and osteomyelitis

Right neonatal mastitis in a female infant

Clinical Features

• Presentation within 2 months of life with redness overlying the breast tissue and/or possibly purulent discharge from one, or rarely both, nipples.
  • The affected breast may be apparently tender to the touch on exam.
  • Palpable fluctuance suggestive of abscess may or may not be present.
• Parents may also report other concurrent, but nonspecific concerns such as
  • poor feeding
  • increased fussiness
  • inconsolability
  • subjective or measured fevers
  • lethargy

Differential Diagnosis

• Cellulitis
• Necrotizing soft tissue infections
• Pediatric fever of uncertain source
• Sepsis (peds)
• Physiologic breast hypertrophy (Neonatal Mastauxe/Giant Mastauxe)

Diagnostic Evaluation of the Febrile and/or Ill-Appearing Infant

• Initiate a complete SBI workup for Pediatric fever of uncertain source
  • Neonatal Mastitis should not be relied upon as a diagnosis to exclude other SBI in the febrile or ill-appearing infant
• Consider Sepsis (peds) alerts and bundles per local protocol

Diagnostic Evaluation of the Afebrile, Well-Appearing Infant

• Complete, head-to-toe physical examination
  • The infant may have varying degrees of normal breast tissue hypertrophy bilaterally, but lack of breast tissue hypertrophy is not specific against the diagnosis.
• Laboratory workup to include
  • Complete blood count
  • Basic metabolic panel
  • Consider blood cultures
  • Consider sending swabs for local site cultures
    • Catheterized urine sample and LP are not required

• Imaging
  • POCUS assessment for abscess in the ER has not been studied
  • Radiology ultrasounds may be ordered at consultant/admitting provider request or per local protocol, may help to identify abscess and guide surgical decision making

Diagnosis

• Neonatal mastitis is a clinical diagnosis which does not require imaging or microbiological confirmation to plan for disposition or begin treatment.
• Other diagnoses, such as sepsis, disseminated cellulitis, or necrotizing fasciitis may be made concurrently and should be managed appropriately.

Management

• Initiate IV antibiotics unless strong cause to consider discharge and close outpatient follow-up exists.
  • Antibiosis should focus on anti-staphylococcal coverage with consideration given for local MRSA proliferation.
    • IV Nafcillin is generally a reasonable first choice. Consider consultation with a clinical pharmacist or the likely admitting team to assist with dosing.

Disposition

• Patients diagnosed with neonatal mastitis should generally be admitted for antibiosis and close monitoring in the NICU.
  • Though mortality is very low in the largest multi-center study, severe sequelae have been documented.
  • A heavy preference for IV nafcillin as a first-choice antibiotic is shown throughout current literature when MRSA is not strongly suspected.
• If considering discharge with oral antibiotics, strongly consider a consultation with a neonatologist to confirm local practice trends or direct conversation with the patient's pediatrician for confirmation of close follow-up.

See Also

• pediatric fever of uncertain source
• Sepsis (peds)
• Mastitis

External Links

Pediatric EM Morsels: Mastitis