What is the first-line antibiotic treatment for pediatric cellulitis?

First-Line Antibiotic Treatment for Pediatric Cellulitis

For typical cases of pediatric cellulitis without systemic signs of infection, the first-line antibiotic treatment should be an agent active against streptococci, such as penicillin, amoxicillin, dicloxacillin, or cephalexin. 1

Classification and Causative Organisms

• Cellulitis is an infection of the deep dermis and subcutaneous tissue, presenting with expanding erythema, warmth, tenderness, and swelling 2
• Most cases of cellulitis are caused by beta-hemolytic streptococci, with Staphylococcus aureus being a less common cause unless associated with an abscess or penetrating trauma 1
• Cellulitis can be classified as purulent (associated with purulent drainage or exudate) or nonpurulent 1

First-Line Treatment Algorithm

For Nonpurulent Cellulitis (Most Common Type):

• Oral therapy options (for mild cases):

  • Cephalexin 25-50 mg/kg/day divided 4 times daily 1
  • Dicloxacillin 25-50 mg/kg/day divided 4 times daily 1
  • Amoxicillin 50 mg/kg/day divided 3 times daily 1
  • Clindamycin 10-30 mg/kg/day divided 3 times daily (for penicillin-allergic patients) 1

• Intravenous therapy options (for moderate to severe cases):

  • Cefazolin 100 mg/kg/day divided every 8 hours 1, 3
  • Nafcillin 100-150 mg/kg/day divided every 6 hours 1
  • Clindamycin 40 mg/kg/day divided every 8 hours (for penicillin-allergic patients) 1

For Purulent Cellulitis or MRSA Risk Factors:

• Consider empiric coverage for CA-MRSA in patients with:

  • Purulent drainage or exudate 1
  • Evidence of MRSA infection elsewhere 1
  • Penetrating trauma 1
  • Nasal colonization with MRSA 1
  • Injection drug use 1
  • Systemic inflammatory response syndrome 1

• Oral options for CA-MRSA coverage:

  • Clindamycin 10-30 mg/kg/day divided 3 times daily 1
  • Trimethoprim-sulfamethoxazole (for children >2 months) 1
  • Doxycycline (for children >8 years) 1

Duration of Therapy

• 5 days of antibiotic therapy is recommended for uncomplicated cellulitis 1
• Treatment should be extended if the infection has not improved within 5 days 1
• Individualize duration based on clinical response 1

Adjunctive Measures

• Elevation of the affected area to promote gravity drainage of edema and inflammatory substances 1
• Treat predisposing conditions such as tinea pedis, trauma, or venous eczema 1
• Examine interdigital toe spaces in lower-extremity cellulitis, as treating fissuring or maceration may reduce recurrence 1

Hospitalization Criteria

• Consider hospitalization for:
  • Systemic inflammatory response syndrome 1
  • Altered mental status 1
  • Hemodynamic instability 1
  • Concern for deeper or necrotizing infection 1
  • Poor adherence to therapy 1
  • Severe immunocompromise 1
  • Failure of outpatient treatment 1

Common Pitfalls and Caveats

• MRSA is an unusual cause of typical cellulitis without purulence; beta-lactams remain effective in most cases 1
• Blood cultures are not routinely recommended for typical cases of cellulitis 1
• Cultures should be obtained in patients with severe systemic features, immunocompromise, or unusual predisposing factors 1
• Avoid unnecessary broad-spectrum antibiotics for typical cellulitis, as narrower spectrum agents targeting streptococci are effective 1, 4
• In some patients, inflammation may worsen after initiating therapy due to sudden destruction of pathogens releasing inflammatory enzymes 1