In a child with fever, irritability, and an enlarging, warm, tender, erythematous swelling of the lower left leg without fluctuance or systemic toxicity, what is the most appropriate initial treatment?

Management of Pediatric Cellulitis with Systemic Symptoms

This child requires immediate hospitalization with IV antibiotics and urgent surgical consultation. The combination of fever, irritability, and an enlarging, warm, tender lower leg swelling without fluctuance represents cellulitis with systemic involvement that mandates parenteral therapy and close monitoring for potential necrotizing infection. 1

Why IV Antibiotics Are Mandatory

• Systemic symptoms (fever and irritability) in a child with spreading soft tissue infection mandate parenteral antibiotic therapy to achieve rapid bactericidal levels, as the progressive erythema reflects active bacterial proliferation. 1

• Oral antibiotics (including oral flucloxacillin) are appropriate only for mild, localized cellulitis in well-appearing children without systemic manifestations—they are insufficient when fever and irritability are present. 1

• Topical antimicrobial agents have no therapeutic role for cellulitis accompanied by systemic signs and should not be used. 1

Why Surgical Consultation Is Required at Admission

• Obtain surgical consultation at admission, not just if the patient fails to improve, as recommended by the Surgical Infection Society. 1 This is critical because:

• The "hard, wooden feel" of subcutaneous tissue, pain disproportionate to findings, and failure to respond to initial antibiotics are features that suggest necrotizing fasciitis, which requires urgent surgical debridement. 2

• Children may initially appear hemodynamically stable yet harbor serious bacterial infection; rapid decompensation can occur despite normal vital signs. 1 The fact that "all vitals are stable" does not exclude severe infection.

• Edema or tenderness extending beyond the cutaneous erythema, and an enlarging area of involvement, are warning signs that deeper tissue may be involved. 2

Initial Management Protocol

Before antibiotic administration:

• Obtain blood cultures before starting antibiotics. 1
• Consider aspiration of the leading edge of cellulitis for Gram stain and culture if diagnosis is uncertain. 1

Antibiotic regimen:

• Initiate cefazolin or ceftriaxone IV as first-line therapy for suspected cellulitis in a child. 1
• Add vancomycin if community-acquired MRSA is prevalent in your region or the child appears toxic. 1

Monitoring:

• Reassess within 24-48 hours for clinical improvement. 1
• Consider imaging (CT or MRI) and possible surgical exploration if there is lack of improvement or progression, though clinical judgment remains paramount and imaging should not delay treatment. 2, 1

Critical Pitfalls to Avoid

• Do not assume hemodynamic stability means the infection is mild—children can decompensate rapidly despite initially normal vital signs. 1

• Do not delay antibiotic administration while awaiting imaging or culture results in a systemically ill child. 1

• Do not rely on outpatient oral therapy with follow-up when systemic symptoms are present—this represents inadequate treatment that risks progression to necrotizing infection. 1

• Incision and drainage is indicated solely for purulent collections; it is not recommended for non-fluctuant cellulitis lacking an abscess. 1

Duration and Transition

• Continue IV antibiotics until the child is afebrile, systemically well, and shows clear clinical improvement, typically 2-3 days minimum. 1

• Transition to oral antibiotics to complete 7-14 days total therapy once improvement is documented. 1