Atraumatic (sinus-related) (Streptococcus pneumoniae · Streptococcus pyogenes · Streptococcus anginosus group · Haemophilus influenzae (non-typeable or type b if underimmunized) · oral anaerobes in chronic sinusitis (CPS 2026, RCH))
Traumatic (skin flora) (Staphylococcus aureus · Streptococcus pyogenes — following periocular trauma or insect bite with broken skin (CPS, UCSF))
Dose is calculated using the amoxicillin component.
Max 875 mg/dose (amoxicillin) · Max 1750 mg/day · Duration: 7–10 days · 45 mg/kg/day amoxicillin component divided BID — covers streptococci, H. influenzae, and anaerobes for atraumatic/sinus-associated preseptal cellulitis (CPS, RCH, UCSF)
• Diagnosis: unilateral eyelid erythema and edema **anterior to orbital septum** (preseptal) — globe not involved; painful/tender eyelid without proptosis, ophthalmoplegia, or vision change (CPS 2026, RCH, NICE principles).
• Oral therapy when: well-appearing child, mild swelling, tolerating oral intake, reliable caregiver follow-up within 24 h, and **no red flags for orbital cellulitis** (RCH, CPS EPOCH studies, AAP).
• Amoxicillin/clavulanate preferred for atraumatic preseptal cellulitis and sinus-associated disease — covers streptococci, H. influenzae, and anaerobes (CPS 2026, UCSF sinus pathway).
• Traumatic preseptal cellulitis without sinusitis: cephalexin may be sufficient per CPS/RCH — use amox-clav if sinusitis coexistence or polymicrobial concern.
• Incomplete Hib vaccination or living in Hia-endemic area: treat as **moderate/severe** — hospitalize with IV therapy (RCH, CPS 2026).
Enter weight on Kids to calculate doses
Cephalexin • p.o. • 25–25 mg/kg/dose • 3×/day
Max 500 mg/dose · Max 1500 mg/day · Duration: 7–10 days · CPS/RCH first-line for traumatic preseptal cellulitis (skin flora) — RCH 20 mg/kg/dose TID max 750 mg
• Cephalexin: traumatic preseptal cellulitis with broken periocular skin and no sinusitis — CPS 2026 pathway (PO cephalexin / IV cefazolin).
• Clindamycin: MRSA suspected (high local prevalence, prior MRSA, failed beta-lactam) or non-anaphylactic penicillin allergy — RCH moderate pathway.
• Hospitalize if: age <1 year (many protocols), moderate–severe swelling, systemic toxicity, unreliable follow-up, or any orbital red flag — switch to hospitalized variant (CPS, RCH, NICE).
• Ophthalmology consultation: diagnostic uncertainty, vision symptoms, proptosis, painful eye movements, or no improvement at 24–48 h (CPS 2026, RCH).
• Neonatal periocular infection: consider gonococcal/chlamydial etiology — send PCR swabs; treat per neonatal conjunctivitis/ophthalmia neonatorum protocols, not standard preseptal regimen (RCH).
Enter weight on Kids to calculate doses
Clinical notes
• Diagnostic criteria: unilateral eyelid erythema, edema, and tenderness with normal globe motility, no proptosis, normal visual acuity, and no RAPD — infection anterior to orbital septum (preseptal/periorbital) (CPS 2026, RCH, StatPearls).
• Oral therapy indications: well child with mild preseptal cellulitis, reliable follow-up, and exclusion of orbital cellulitis — EPOCH studies support selected home oral therapy (CPS, RCH, Clin Exp Ophthalmol).
• Hospitalization indications: moderate–severe disease, age <12 months (per local protocol), incomplete Hib immunization, fever with toxicity, inability to tolerate oral antibiotics, or concern for orbital extension (CPS 2026, RCH).
• Ophthalmology consultation: any red flag for orbital involvement, visual symptoms, diagnostic uncertainty in young children, or lack of improvement at 24–48 h — urgent if proptosis, ophthalmoplegia, or decreased acuity (CPS, RCH, NICE).
• Orbital red flags: proptosis, painful/restricted extraocular movements, diplopia, decreased visual acuity, RAPD, chemosis, severe headache, or altered consciousness — **orbital cellulitis emergency** requiring IV cephalosporin ± MRSA coverage, imaging, and ENT/ophthalmology (CPS 2026, RCH).
