Cellulitis

Source: Fish DN, Pendland SL, Danziger LH. Skin and Soft-Tissue Infections. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 8th edition. http://accesspharmacy.com/content.aspx?aid=8002378. Accessed July 21, 2012.

• Acute, spreading, infectious process that initially affects epidermis and dermis; may subsequently spread within superficial fascia.
  • Process characterized by inflammation but with little or no necrosis or suppuration of soft tissue.

• Most often caused by S. pyogenes or S. aureus.
• Increased incidence of methicillin-resistant S. aureus (MRSA) of major concern.
• Mixed aerobic and anaerobic pathogens seen:
  • In diabetics
  • Following traumatic injuries
  • At sites of abdomen or perineum surgical incisions
  • With compromised host defenses (e.g., vascular insufficiency)

• Spreading inflammatory infection following wound from minor trauma, abrasion, ulcer, or surgery.

• Considered a serious infection due to propensity to spread through lymphatic tissue and to bloodstream.
• 10% of all infection-related hospital admissions between 1998 and 2006

• Good wound care

• Injection drug use
• History of antecedent wound from minor trauma, abrasion, ulcer, or surgery.
• Poor nutrition

• Characterized by erythema and edema of the skin.

Signs and Symptoms

• Fever
• Chills
• Malaise
• Erythema and edema of skin; affected areas warm to touch
• Lesions nonelevated, with poorly defined margins
• Inflammation present, with little or no necrosis or suppuration of soft tissue
• Tender lymphadenopathy

Means of Confirmation and Diagnosis

• Diagnosis usually based on appearance of lesion.

Laboratory Tests

• Complete blood count (CBC): leukocytosis common.
• Cultures of affected area may be difficult.
• Gram stain of fluid obtained by injection and aspiration of saline.
• Blood cultures: bacteremia present in as many as 30% of cellulitis cases.

Diagnostic Procedures

• Injection and aspiration of 0.5 mL saline into advancing edge of lesion may aid microbiologic diagnosis, but is often negative.

Differential Diagnosis

• Deep venous thrombosis
• Venous stasis
• Candidiasis

• Rapid eradication of infection
• Prevention of complications

• Selection of antimicrobial therapy directed toward type of bacteria documented to be present or suspected.

• Elevation and immobilization of involved area to decrease local swelling
• Cool, sterile saline dressings may decrease pain.
  • Follow with moist heat to aid in localization of infection.
  • Surgical incision and drainage rarely indicated in uncomplicated disease.

• Administration of semisynthetic penicillin (nafcillin or oxacillin) or first-generation cephalosporin (cefazolin) recommended until definitive diagnosis, by skin or blood cultures, can be made (Tables 1 and 2).
• Oral or parenteral clindamycin recommended for penicillin-allergic patients.
• Usual duration of therapy: 5–10 days
  • If caused by gram-negative bacilli or mixture of microorganisms, treat for 10–14 days.