What is the recommended treatment regimen and duration for periorbital (pre‑septal) cellulitis in a healthy child or adult?

Periorbital (Preseptal) Cellulitis: Treatment and Duration

For uncomplicated periorbital cellulitis in children and adults, prescribe oral beta-lactam monotherapy (cephalexin 500 mg every 6 hours or amoxicillin-clavulanate 875/125 mg twice daily) for exactly 5 days if clinical improvement occurs; extend only if symptoms persist. 1, 2

First-Line Antibiotic Selection

Pediatric Patients

• Amoxicillin-clavulanate is the preferred first-line oral agent for typical uncomplicated periorbital cellulitis in children, dosed appropriately for weight 2
• Alternative oral beta-lactams include cephalexin, dicloxacillin, or cefdinir, all providing excellent coverage against Streptococcus pyogenes and methicillin-sensitive S. aureus, the primary pathogens 2, 3
• Clindamycin 10–13 mg/kg/dose every 6–8 hours (maximum 40 mg/kg/day) is appropriate when MRSA coverage is needed or for penicillin allergy, but use only if local clindamycin resistance rates are <10% 2

Adult Patients

• Cephalexin 500 mg orally every 6 hours or dicloxacillin 250–500 mg every 6 hours for 5 days provides optimal streptococcal and MSSA coverage 1
• Amoxicillin-clavulanate 875/125 mg twice daily is an acceptable alternative, particularly when broader coverage is desired 1
• Beta-lactam monotherapy achieves approximately 96% clinical success in typical nonpurulent periorbital cellulitis 1

Treatment Duration: The 5-Day Rule

Treat for exactly 5 days if clinical improvement has occurred (reduced warmth, tenderness, erythema, and absence of fever); extend only if symptoms have not improved within this timeframe. 1, 2

• High-quality randomized controlled trial evidence demonstrates that 5-day courses are as effective as 10-day courses for uncomplicated cellulitis 1
• Traditional 7–14 day regimens are no longer necessary and promote unnecessary antibiotic resistance 1
• Residual erythema alone does not warrant extension—inflammation may persist for 1–2 weeks after bacterial eradication 1

Intravenous Therapy for Complicated Cases

When to Hospitalize

Admit patients with periorbital cellulitis when any of the following are present:

• Age <6 months with moderate-to-severe disease 1
• Systemic inflammatory response syndrome (fever >38°C, tachycardia, hypotension, altered mental status) 1
• Concern for progression to orbital (postseptal) cellulitis 4, 5
• Severe immunocompromise or neutropenia 1
• Failure of outpatient therapy after 24–48 hours 1

Intravenous Antibiotic Regimens

• Ceftriaxone plus clindamycin is the most commonly used IV combination, with mean duration of 8.6 days in hospitalized children 3
• Vancomycin 15 mg/kg IV every 6 hours is first-line for complicated cases requiring MRSA coverage (A-II evidence) 2
• Clindamycin 10–13 mg/kg/dose IV every 6–8 hours is an alternative for stable children if local MRSA resistance is <10%, with transition to oral therapy when the isolate is susceptible 2
• Linezolid (10 mg/kg IV every 8 hours for children <12 years; 600 mg IV twice daily for ≥12 years) is another IV option 2
• Treatment duration for complicated infections is typically 7–14 days, individualized based on clinical response 1, 2

When to Add MRSA Coverage

Add empirical MRSA-active antibiotics ONLY when specific risk factors are present: 1, 2

• Penetrating trauma or injection drug use 1, 2
• Purulent drainage or exudate from the infection site 1, 2
• Known MRSA colonization or prior MRSA infection 1, 2
• Systemic inflammatory response syndrome 1, 2
• Failure to respond to initial beta-lactam therapy after 48–72 hours 1, 2

MRSA is an uncommon cause of typical periorbital cellulitis even in high-prevalence settings—routine coverage provides no benefit and promotes resistance 1

Distinguishing Preseptal from Postseptal (Orbital) Cellulitis

Clinical Red Flags Requiring Imaging

• Proptosis and limitation of extraocular movements indicate postseptal inflammation 4
• Severe pain out of proportion to examination, rapid progression, or vision changes 4, 5
• Age >3 years, high neutrophil count, absence of infectious conjunctivitis, gross periorbital edema, or previous antibiotic therapy increase risk of postseptal disease 4

Imaging Recommendations

• CT orbits with IV contrast is the most useful imaging for suspected orbital cellulitis, differentiating preseptal from postseptal disease and detecting complications (superior ophthalmic vein thrombosis, cavernous sinus thrombosis, subdural empyema) 4
• MRI orbits with and without IV contrast may be complementary when more detailed assessment of intraorbital spread or intracranial complications is warranted 4
• Imaging is unnecessary for straightforward preseptal cellulitis with typical clinical features 4, 6

Common Predisposing Factors

• Upper respiratory infection (68%) and trauma to the eyelids (20%) are the most common predisposing factors in periorbital cellulitis 3
• Sinusitis (particularly ethmoid sinusitis) is more frequently associated with orbital cellulitis (79%) 4, 3
• Other risk factors include odontogenic infections, insect bites, and periocular trauma 6, 7

Microbiology

• Blood and skin cultures are usually negative in periorbital cellulitis 3
• When isolated, the most common pathogens are Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes 3, 7, 8
• Streptococcus species are the predominant causative agents overall 3

Critical Pitfalls to Avoid

• Do not reflexively add MRSA coverage for typical nonpurulent periorbital cellulitis without specific risk factors—this represents overtreatment 1, 2
• Do not continue ineffective antibiotics beyond 48–72 hours—treatment failure indicates either resistant organisms or progression to orbital cellulitis requiring reassessment 1, 2
• Do not delay imaging or surgical consultation when signs of orbital involvement or intracranial complications develop 4, 5
• Do not automatically extend therapy to 7–10 days based solely on residual erythema; extend only if warmth, tenderness, or erythema have not improved after 5 days 1
• Do not use doxycycline or trimethoprim-sulfamethoxazole as monotherapy for typical periorbital cellulitis, as they lack reliable activity against beta-hemolytic streptococci 1, 2

Adjunctive Measures

• Elevate the head to promote gravity drainage of periorbital edema 1
• Treat predisposing conditions such as sinusitis, upper respiratory infections, or chronic rhinitis 1, 3
• Reassess patients within 24–48 hours to verify clinical response, as treatment failure rates of approximately 21% have been reported with some oral regimens 1

Surgical Intervention

• Intravenous antibiotics alone are effective in most patients with periorbital cellulitis 3
• A small proportion (6%) may require surgical intervention for extensive infection or progression to orbital abscess 3, 5
• Surgical therapy is necessary in 49% of patients with true orbital (postseptal) cellulitis, typically involving incision and drainage of orbital abscess 5