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A common global health burden with >650,000 admissions per year in the United States alone (1)
- An acute bacterial infection of the dermis and subcutaneous (SC) tissue
- Types and locations:
- Periorbital cellulitis: bacterial infection of the eyelid and surrounding tissues (anterior compartment)
- Orbital cellulitis: infection of the eye posterior to the septum; sinusitis is most common risk factor.
- Facial cellulitis: preceded by upper respiratory infection or otitis media
- Buccal cellulitis: infection of cheek in children associated with bacteremia (common before Haemophilus influenzae type B vaccine)
- Peritonsillar cellulitis: common in children; associated with fever, sore throat, and “hot potato” speech
- Abdominal wall cellulitis: common in morbidly obese patients
- Perianal cellulitis: sharply demarcated, bright, perianal erythema
- Necrotizing cellulitis: gas-producing bacteria in the lower extremities; more common in diabetics
- Predominant sex: male = female
- Seasonality increased hospitalizations for cellulitis in the summer with fewer in the winter months (2).
- The exact prevalence is uncertain because cellulitis is common and not reportable. It affects all age groups and all races; however, certain types of cellulitis/microorganisms occur in certain populations.
- In the United States, ~14.5 million annual cases of cellulitis account for $3.7 billion in ambulatory costs (1).
Etiology and Pathophysiology
Cellulitis is caused by bacterial penetration through a break in the skin. Hyaluronidase mediates SC spread.
- β-Hemolytic streptococci (groups A, B, C, G, and F), Staphylococcus aureus, including MRSA, and gram-negative aerobic bacilli are most common.
- S. aureus seen in periorbital and orbital cellulitis and IV drug users
- Pseudomonas aeruginosa seen in diabetics and other immunocompromised patients
- H. influenza causes buccal cellulitis.
- Clostridia and non–spore-forming anaerobes: necrotizing cellulitis (crepitant/gangrenous)
- Streptococcus agalactiae: cellulitis following lymph node dissection
- Pasteurella multocida and Capnocytophaga canimorsus: cellulitis preceded by bites
- Streptococcus iniae: immunocompromised hosts
- Rare causes: Mycobacterium, fungal (mucormycosis, aspergillosis, syphilis)
No genetic pattern
- Disruption of skin barrier: trauma, infection, insect bites, injection drug use, body piercing
- Inflammation: eczema or radiation therapy
- Edema due to venous insufficiency; lymphatic obstruction due to surgery or congestive heart failure (CHF)
- Elderly, diabetes, hypertension, obesity
- Recurrent cellulitis:
- Cellulitis recurrence score (predicts recurrence of lower extremity cellulitis based on presence of lymphedema, chronic venous insufficiency, peripheral vascular disease, and deep venous thrombosis) (3)[A]
- Recurrent cellulitis is seen in immunocompromised patients (HIV/AIDS), steroids and TNF-α inhibitor therapy, diabetes, hypertension, cancer, peripheral arterial or venous diseases, chronic kidney disease, dialysis, IV or SC drug use (3).
- Good skin hygiene
- Support stockings to decrease edema
- Maintain tight glycemic control and proper foot care in diabetic patients.