Cellulitis

Descriptive text is not available for this image BASICS

Skin and soft tissue infections (SSTIs) are a common health burden with approximately a quarter of patients requiring hospitalization, leading to >650,000 admissions per year in the United States.

DESCRIPTION

  • Acute bacterial infection of the dermis and subcutaneous tissue
  • Types and locations:
    • Most common on lower extremities, unilateral
    • Periorbital cellulitis: infection of the eyelid and surrounding tissues
    • Orbital cellulitis: infection of the eye posterior to the septum; most common risk factor is sinusitis.
    • Facial cellulitis: preceded by URI 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
    • Perianal cellulitis: sharply demarcated, bright, perianal erythema
    • Necrotizing cellulitis: gas-producing bacteria in the lower extremities; more common in diabetics

EPIDEMIOLOGY

  • Predominant sex: male = female
  • Increased hospitalizations for cellulitis in the summer and fewer in the winter months

Incidence

1.5 to 24.6 per 1,000 person-years with recurrence rate ranging from 16% to 53% within 3 years.

Prevalence

Visits to U.S. ambulatory practices for purulent SSTI range from 5.4 to 11.3 million visits annually.

ETIOLOGY AND PATHOPHYSIOLOGY

Caused by bacterial penetration through a compromise in the epidermis into the deep dermis and subcutaneous tissues.

  • Microbiology
    • β-Hemolytic streptococci (groups A, B, C, G, and F), staphylococci (Staphylococcus aureus, including MRSA) and gram-negative aerobic bacilli most common
    • S. aureus seen in periorbital and orbital cellulitis and people who inject IV drugs
    • Pseudomonas aeruginosa seen in diabetics and other immunocompromised patients
    • H. influenzae causes buccal cellulitis.
    • Clostridia and non–spore-forming anaerobes: necrotizing cellulitis (crepitant/gangrenous)
    • Streptococcus agalactiae: following lymph node dissection
    • Pasteurella multocida and Capnocytophaga canimorsus: precipitated by bites
    • Streptococcus iniae: immunocompromised hosts
    • Rare causes: Mycobacterium, fungal (mucormycosis, aspergillosis)

Genetics

None

RISK FACTORS

  • Disruption of skin barrier from trauma, infection, insect bites, injection drug use, body piercing, maceration, ulcerations, chronic wounds, fissured toe webs
  • Inflammation from excoriating skin disorders or radiation therapy
  • Edema due to venous insufficiency; lymphatic obstruction due to surgery or congestive heart failure
  • Advanced age, male gender, diabetes, hypertension (HTN), cancer, obesity
  • Dermatomycosis, tinea pedis, onychomycosis, presence of S. aureus and/or streptococci in toe webs
  • Previous episode of cellulitis
  • 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)
    • 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.

GENERAL PREVENTION

  • Good skin hygiene and hydration to avoid dryness and cracking
  • Management of edema with elevation, compression stockings, pneumatic pressure pumps
  • Maintain glycemic control and proper foot care in diabetic patients.

COMMONLY ASSOCIATED CONDITIONS

Abscess, lymphedema, venous insufficiency, stasis dermatitis, obesity

There's more to see -- the rest of this topic is available only to subscribers.