What is the recommended amoxicillin‑clavulanate (Augmentin) dose for a 20‑kg child with acute bacterial sinusitis, and what alternative treatments should be used if the child has an IgE‑mediated penicillin allergy?

Amoxicillin‑Clavulanate (Augmentin) Dosing for Pediatric Acute Bacterial Sinusitis

Recommended Dose for a 20‑kg Child

For a 20‑kg child with acute bacterial sinusitis, prescribe high‑dose amoxicillin‑clavulanate 1,800 mg amoxicillin/128 mg clavulanate per day, divided into two doses of 900 mg/64 mg every 12 hours. 12

• The American Academy of Pediatrics recommends 80–90 mg/kg/day of the amoxicillin component with 6.4 mg/kg/day of clavulanate, divided twice daily for children with risk factors such as age < 2 years, daycare attendance, or recent antibiotic use within the past 4–6 weeks. 12
• For a 20‑kg child, this calculates to 1,600–1,800 mg amoxicillin per day (80–90 mg/kg × 20 kg) plus 128 mg clavulanate per day (6.4 mg/kg × 20 kg), administered as 800–900 mg amoxicillin/64 mg clavulanate twice daily. 12
• This high‑dose regimen provides superior coverage against β‑lactamase‑producing Haemophilus influenzae and Moraxella catarrhalis, as well as penicillin‑resistant Streptococcus pneumoniae. 13

Treatment Duration

• Continue therapy for a minimum of 10–14 days total, or for 7 days after the child becomes symptom‑free (whichever is longer). 124
• This individualized approach ensures at least 10 days of treatment while avoiding prolonged therapy in children who improve rapidly. 12

Critical 72‑Hour Reassessment

• Reassess the child at 72 hours after starting antibiotics: if symptoms are worsening or failing to improve, this indicates treatment failure. 124
• Treatment failure at 72 hours suggests β‑lactamase‑producing organisms that require clavulanate coverage, or the child may already be on high‑dose therapy and need escalation to parenteral ceftriaxone. 124

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Alternative Treatment for IgE‑Mediated Penicillin Allergy

First‑Line Alternative: Second‑ or Third‑Generation Cephalosporins

For a child with non‑severe (non‑Type I) penicillin allergy, prescribe a second‑ or third‑generation oral cephalosporin for 10 days. 124

• Cefdinir, cefuroxime axetil, or cefpodoxime proxetil are appropriate alternatives because cross‑reactivity with penicillin is negligible in non‑anaphylactic allergy. 124
• These agents provide excellent coverage against S. pneumoniae, H. influenzae, and M. catarrhalis. 15

Severe (Type I/Anaphylactic) Penicillin Allergy

For a child with documented severe (Type I/anaphylactic) penicillin allergy, prescribe a respiratory fluoroquinolone such as levofloxacin or moxifloxacin, recognizing the usual avoidance of this class in children. 2

• Respiratory fluoroquinolones provide 90–92 % predicted clinical efficacy against multidrug‑resistant S. pneumoniae and β‑lactamase‑producing organisms. 1
• However, fluoroquinolones are typically reserved for severe allergy or treatment failure in pediatrics due to concerns about cartilage toxicity, though this risk is theoretical and not well‑documented in clinical practice. 2

Alternative for Vomiting or Non‑Compliance

If the child is vomiting, cannot tolerate oral medications, or is unlikely to take initial antibiotic doses, administer ceftriaxone 50 mg/kg (1,000 mg for a 20‑kg child) as a single intramuscular or intravenous dose. 24

• After clinical improvement (typically within 24 hours), switch to oral antibiotics to complete the 10–14 day course. 24
• Ceftriaxone provides 95–100 % coverage against the three major sinusitis pathogens and is safe even in most penicillin‑allergic children because cross‑reactivity with second‑ and third‑generation cephalosporins is minimal. 4

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Agents to Avoid in Penicillin‑Allergic Children

• Azithromycin and trimethoprim‑sulfamethoxazole should never be used because resistance rates in S. pneumoniae and H. influenzae exceed 20–25 %. 126
• The American Academy of Pediatrics explicitly contraindicates azithromycin for pediatric sinusitis due to these resistance patterns. 12
• First‑generation cephalosporins (e.g., cephalexin) lack adequate coverage against β‑lactamase‑producing H. influenzae and should be avoided. 1

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Red‑Flag Findings Requiring Immediate Escalation

• Suspect orbital or intracranial complications if the child develops any of the following: periorbital swelling, proptosis, impaired extraocular muscle function, severe headache, altered mental status, seizures, or focal neurologic deficits. 24
• Management includes urgent contrast‑enhanced CT imaging, intravenous antibiotics (vancomycin plus ceftriaxone or cefotaxime), and immediate ENT/neurosurgery consultation. 24

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Common Pitfalls to Avoid

• Do not obtain imaging (CT or MRI) for uncomplicated bacterial sinusitis; imaging does not contribute to diagnosis in straightforward cases and is reserved only for suspected complications. 24
• Do not continue ineffective therapy beyond 72 hours; early reassessment and appropriate escalation are essential to prevent treatment failure. 124
• Do not use standard‑dose amoxicillin (45 mg/kg/day) in high‑risk children (age < 2 years, daycare, recent antibiotics); these children require high‑dose amoxicillin‑clavulanate from the start. 12