What is the appropriate management of unilateral parotitis in a two‑month‑old infant?

Management of Unilateral Parotitis in a 2-Month-Old Infant

Admit the infant for intravenous anti-staphylococcal antibiotics (nafcillin or oxacillin) immediately, ensure adequate hydration, and perform ultrasound imaging to rule out abscess formation.

Diagnostic Approach

Confirm acute suppurative parotitis by identifying the classic triad: unilateral parotid swelling, erythema over the gland, and purulent discharge expressible from Stensen's duct 1, 2. At 2 months of age, this presentation is rare but serious, requiring urgent evaluation 1, 2.

• Obtain purulent material from Stensen's duct for Gram stain and culture before starting antibiotics, as this guides definitive therapy 1, 2.
• Order ultrasound of the affected parotid gland to assess for abscess formation, areas of necrosis, or diffuse enlargement 2, 3.
• Check complete blood count to identify leukocytosis, which is present in approximately 46% of pediatric inpatients with parotitis and signals more severe infection 4.

Immediate Management

Hospitalize all infants under 6 months with suspected suppurative parotitis because of their high risk for dehydration, bacteremia, and rapid progression to abscess 2, 4.

Antibiotic Therapy

• Start empiric intravenous anti-staphylococcal coverage immediately, as Staphylococcus aureus (including penicillin-resistant strains) is the causative organism in the majority of neonatal cases 1, 5, 2, 3.
• Nafcillin or oxacillin (150–200 mg/kg/day divided every 6 hours IV) is first-line for methicillin-susceptible S. aureus 5, 2.
• Add vancomycin (15 mg/kg/dose IV every 6–8 hours, adjusted for renal function) if the infant has risk factors for MRSA (prior hospitalization, NICU stay, or known MRSA colonization) or if the Gram stain shows gram-positive cocci in clusters 5, 2.
• Broaden coverage to include anaerobes and gram-negative organisms (ampicillin-sulbactam 100–150 mg/kg/day IV divided every 6 hours) if the infant appears toxic, has failed initial therapy, or has polymicrobial infection on culture 5, 2.

Supportive Measures

• Ensure aggressive intravenous hydration, as dehydration is present in 46% of hospitalized pediatric parotitis cases and contributes to ductal stasis 4.
• Perform gentle bimanual massage of the parotid gland to promote drainage through Stensen's duct and reduce bacterial load 1, 2.
• Encourage non-nutritive sucking or pacifier use to stimulate salivary flow, which mechanically flushes bacteria from the duct 2.

Surgical Intervention

Consult pediatric surgery or otolaryngology urgently if:

• Ultrasound demonstrates a discrete abscess requiring incision and drainage 2, 4.
• The infant fails to improve within 48–72 hours of appropriate IV antibiotics (persistent fever, worsening swelling, or increasing leukocytosis) 2, 4.
• Fluctuance develops on physical examination, indicating organized pus 2, 4.

Surgical drainage is required in approximately 15% of hospitalized pediatric parotitis cases and should not be delayed once an abscess is confirmed 4.

Duration of Therapy

• Continue IV antibiotics for a minimum of 10 days, adjusting based on culture results and clinical response 1, 2.
• Transition to oral antibiotics (e.g., cephalexin 25–50 mg/kg/day divided every 6 hours) only after the infant is afebrile for 48 hours, swelling is markedly improved, and oral intake is adequate 2.

Monitoring and Follow-Up

• Repeat ultrasound at 48–72 hours if clinical improvement is not evident, to detect evolving abscess or necrosis 2, 3.
• Monitor for complications including facial nerve palsy, osteomyelitis of the mandible, septic thrombophlebitis, and bacteremia, all of which are more common in neonates 5, 2.
• Schedule outpatient follow-up within 1 week after discharge to confirm complete resolution and assess for recurrence 4.

Risk Factors to Address

Identify and correct predisposing conditions that increase susceptibility to neonatal parotitis 2:

• Prematurity and low birth weight (common in reported cases) 1, 2.
• Dehydration or poor oral intake leading to decreased salivary flow 2, 4.
• Immunosuppression or underlying immune deficiency (consider workup if recurrent infections) 3.
• Maternal colonization with S. aureus (e.g., recurrent furunculosis), which may transmit to the neonate 3.

Critical Pitfalls to Avoid

• Do not treat as an outpatient—all infants under 6 months require hospitalization due to rapid progression and high complication rates 2, 4.
• Do not delay imaging—ultrasound is essential to detect abscess, which mandates surgical drainage 2, 3, 4.
• Do not use oral antibiotics alone—parenteral therapy is mandatory in neonates and young infants 1, 5, 2.
• Do not assume viral etiology—while mumps and other viral causes are common in older children, bacterial suppurative parotitis predominates in neonates and requires antibiotics 5, 2.
• Do not overlook MRSA—penicillin-resistant S. aureus is frequently isolated, so empiric coverage must account for this 1, 3.