What is the epidemiology of periorbital cellulitis?

Epidemiology of Periorbital Cellulitis

Periorbital cellulitis is more common than orbital cellulitis, affecting primarily preschool-aged children under 5 years, with a male predominance and seasonal peaks in spring and fall. 1, 2

Demographic Features

• Age distribution:

  • Mean age: 3.7-4.1 years 1, 2
  • 85% of periorbital cellulitis cases occur in children younger than 5 years 1
  • Orbital cellulitis tends to affect older children (62% older than 5 years) 1

• Gender distribution:

  • Male to female ratio of approximately 1.3-1.7:1 2, 3

• Seasonal patterns:

  • Higher incidence during spring and fall months 3

Predisposing Factors

The most common predisposing factors for periorbital cellulitis include:

1. Upper respiratory tract infections (68% of cases) 1
2. Trauma to the eyelids (20-23% of cases) 1, 2
3. Sinusitis (24.8% of cases) 2
   • Note: Sinusitis is more commonly associated with orbital cellulitis (79-90% of cases) 1, 4
4. Ocular conditions (13.7% of cases) 2

Microbiology

The most commonly isolated pathogens in periorbital cellulitis are:

• Staphylococcus aureus (most common, 41.9% of culture-positive cases) 3
• Streptococcus pneumoniae 1
• Staphylococcus epidermidis 1
• Coagulase-negative staphylococci (25.8% of culture-positive cases) 3
• Haemophilus influenzae type b (6% of culture-positive cases) 3

Important microbiological patterns:

• Blood cultures are typically negative in periorbital cellulitis related to trauma or external infection (99%) 4
• Blood cultures are more frequently positive (42%) in periorbital cellulitis related to upper respiratory infections 4
• Overall culture positivity rate is relatively low (30-39% of clinical samples) 3

Geographic and Temporal Variations

• According to the Infectious Diseases Society of America (IDSA), the epidemiology of bacterial keratitis varies by geographic location 5:
  • Gram-negative organisms are more prevalent in southern US locations than in northern United States
  • South Florida has higher rates of gram-negative organisms than other areas of the country
  • Regional variations may be associated with climate, rural versus urban settings, and etiology of infection

Clinical Presentation Patterns

• Periorbital cellulitis is more common (83-93% of cases) than orbital cellulitis (7-17% of cases) 1, 3
• Laboratory markers tend to be more elevated in orbital cellulitis compared to periorbital cellulitis:
  • Higher white blood cell counts
  • Higher erythrocyte sedimentation rates
  • Higher C-reactive protein levels 3

Treatment Patterns

• Most cases (90-100%) can be successfully managed with intravenous antibiotics alone 1, 4, 2
• Mean duration of intravenous antibiotic therapy: 3.4-8.6 days 1, 2
• Mean duration of oral antibiotic therapy: 8.1 days 2
• Surgical intervention is required in a small percentage (6-10%) of periorbital cellulitis cases 1, 4
• Orbital cellulitis requires surgical intervention more frequently (38% of cases) 4

Complications

• Meningitis can develop in a small percentage of cases (reported in 3 children with periorbital cellulitis related to upper respiratory infection) 4
• With appropriate and timely treatment, most patients recover fully without complications 2

Understanding these epidemiological patterns is crucial for early recognition and appropriate management of periorbital cellulitis, which can help prevent progression to more serious complications.