Cellulitis

Aka: Cellulitis, Staphylococcal Cellulitis

1. See Also
   1. Skin Infection
   2. Hand Infection
   3. Nodular Lymphangitis
   4. Erysipelas
   5. Impetigo
   6. Preseptal Cellulitis and Periorbital Cellulitis
   7. Cellulitis in Diabetes Mellitus
2. Risk factors
   1. Also see Group A Streptococcus Cellulitis (Erysipelas)
   2. Trauma
      1. Laceration
      2. Puncture Wound
      3. Post-operative infection at incision site
   3. Underlying skin lesion
      1. Furuncle
      2. Skin Ulcer
      3. Fungal Dermatoses
      4. Non-Group A Streptococcus Cellulitis related lesions
         1. Coronary Artery bypass with saphenous vein graft
         2. Radical pelvic surgery or radiation
   4. Neoplasms
      1. Lymphatic Cutaneous metastases from neoplasms
      2. Inflammatory Breast Cancer
      3. Carcinoma Erysipeloides
   5. Extremity Stasis or Edema
      1. Chronic Dependent edema (may progress rapidly)
      2. Peripheral Vascular Disease
   6. Perianal Streptococcal Cellulitis (in children)
   7. Diabetes Mellitus
      1. See Cellulitis in Diabetes Mellitus
   8. Immunocompromised patients
3. Causes: Streptococcal and Staphylococcal Cellulitis
   1. Common (most Cellulitis cases)
      1. Staphylococcal Cellulitis
      2. Group A Streptococcus Cellulitis (Erysipelas)
   2. Less common Streptococcal infections
      1. Pneumococcus
      2. Non-Group A Streptococcus Cellulitis
         1. Group C or G Streptococcus Cellulitis
         2. Group B Streptococcus Cellulitis in newborns
   3. Rapidly progressive Cellulitis
      1. See Necrotizing Fasciitis
      2. Vibrio Cellulitis (Vibrio vulnificus)
      3. Clostridium perfringens
      4. Pasteurella multocida
      5. Aeromonas Hydrophila
4. Causes: Exposure
   1. Fish Handlers or water exposure (See Marine Trauma)
      1. Erysipelothrix rhusiopathiae (Erysipeloid)
      2. Mycobacterium marinum (Fish tank exposure)
      3. Aeromonas Hydrophila
      4. Vibrio Cellulitis
   2. Animal Bites
      1. Cat Bites
         1. Pasteurella multocida
      2. Dog Bites
         1. Staphylococcus intermedius
      3. Envenomation spines of stonefish (South Pacific)
         1. Risk of serious systemic toxicity, pulmonary edema
      4. Human Bites
         1. See Fight Bite
   3. Miscellaneous
      1. Pseudomonas aeruginosa
         1. Sweaty Tennis Shoe Syndrome
      2. Eosinophilic Cellulitis
5. Immunocompromised Patients
   1. Serratia
   2. Proteus
   3. Enterobacteriaceae
   4. Cryptococcus
   5. Legionella pneumophila
      1. Associated with Legionella pneumonia
   6. Legionella micdadei
      1. Seen in renal transplant patients
   7. Escherichia coli
      1. Seen in children with relapsing Nephrotic Syndrome
6. Symptoms
   1. Inflamed skin wound develops rapidly days after injury
      1. Local tenderness
      2. Pain
      3. Very red, hot, swollen an painful
   2. Associated symptoms
      1. Malaise, fever, chills
7. Signs
   1. Draw margins of erythema with marker
      1. Follow course of infection on antibiotics
   2. Wound with contiguous inflammation
      1. Erythema (Rubor)
      2. Swelling (Tumor)
      3. Local tenderness (Dolor)
      4. Warm to touch (Calor)
   3. Contrast with findings in Erysipelas
      1. Not elevated
      2. No sharp demarcation
   4. Regional Lymphadenopathy
   5. Local abscesses
   6. Small patches of necrosis
   7. Gram Negative superinfection may also be present
   8. Hemorrhagic and necrotic bullae (specific conditions)
      1. Group A Streptococcal Cellulitis
      2. Pseudomonas Cellulitis
      3. Vibrio Cellulitis (Vibrio vulnificus)
      4. Clostridium perfringens
      5. Aeromonas Hydrophila
8. Differential Diagnosis: Non-infectious Conditions
   1. Vascular Conditions
      1. Superficial thrombophlebitis
      2. Deep Vein Thrombosis
   2. Dermatologic Conditions
      1. Contact Dermatitis
      2. Insect Bites
      3. Acute Drug Reaction
      4. Eosinophilic Cellulitis
      5. Sweet Syndrome
   3. Rheumatologic Conditions
      1. Gouty Arthritis
      2. Relapsing Polychondritis
   4. Miscellaneous
      1. Erythromelalgia
      2. Inflammatory Carcinoma (metastatic cancer to skin)
      3. Foreign body reaction (mesh, metal, silicone implant)
      4. Familial Mediterranean fever
   5. References
      1. Vergidis (2005) Ann Intern Med 142:47-55
9. Labs
   1. Blood Culture (25% sensitivity)
   2. Skin biopsy (25% sensitivity)
   3. Fine Needle Aspiration
   4. Saline injection and aspiration
      1. Listed for historical purposes only (rarely done in clinical practice)
      2. Technique
         1. Leading edge injection and aspiration with saline
      3. Efficacy
         1. May assist diagnosis with Cellulitis
         2. Not useful in Erysipelas
         3. 30% sensitivity from closed lesions (efficacy may be as low as 5%)
      4. Indication
         1. Unusual pathogens suspected
         2. Cellulitis refractory to current antibiotics
10. Management: General Care
    1. Tetanus prophylaxis
    2. Immobilization and elevation of involved limb
       1. Splint in a position of function
       2. Decreases swelling
    3. Clean wound site
       1. Copious irrigation
       2. Debride devitalized tissue
       3. Incision and Drainage if deep fluctuant pocket
    4. Compresses
       1. Cool sterile saline dressings decrease pain
       2. Later, moist heat helps localize infection
11. Management: Extremity Cellulitis
    1. Precaution
       1. MRSA is becoming more common and more resistant
          1. Consider Septra or Doxycycline if MRSA is suspected (Clindamycin may also be considered)
          2. Abscess strongly suggests Staphylococcus aureus, and is high risk for MRSA
       2. Avoid Fluoroquinolones in Cellulitis due to high resistance
    2. Mild to Moderate Infection (uncomplicated)
       1. Course
          1. Standard course has been 10 days of antibiotics
          2. New: 5 day as effective as 10 day if uncomplicated
          3. Hepburn (2004) Arch Intern Med 164:1669-74
       2. Agents
          1. Dicloxacillin 500 mg PO every 6 hours or
          2. Cefazolin 1 g IV every 8 hours or
          3. Augmentin 875 mg PO bid
    3. Severe Infection
       1. Nafcillin 2 g IV every 4 hours or
       2. Oxacillin 2 g IV every 4 hours
    4. Penicillin Allergy
       1. Erythromycin or
       2. Azithromycin or
       3. Clarithromycin or
       4. Clindamycin
    5. Outpatient parenteral (moderate to severe Cellulitis)
       1. Efficacy
          1. As effective as daily Rocephin
       2. Protocol (adults): 7-10 day course
          1. Cefazolin 2 gram IV q24 hours
          2. Probenacid 1 gram PO q24 hours
             1. Decreases Cefazolin excretion
       3. Benefits
          1. Lower cost
          2. More narrow spectrum
       4. References
          1. Grayson (2002) Clin Infect Dis 34:1440-8
12. Management: Facial Cellulitis (Erysipelas)
    1. Mild to Moderate Infection
       1. Augmentin 875 mg PO bid
       2. Cefazolin (Ancef) 1 g IV every 8 hours
    2. Severe Infection
       1. Nafcillin 2 g IV every 4 hours
       2. Oxacillin 2 g IV every 4 hours
       3. Vancomycin 1.0-1.5 g IV qd
13. Management: Cellulitis in comorbid Diabetes Mellitus
    1. See Skin Infections in Diabetes Mellitus
14. Prevention: Recurrent episodes
    1. Reduce peripheral edema (support stockings)
    2. Good skin hygiene
    3. Prophylactic antibiotics:
       1. Efficacy
          1. Not useful if underlying predisposing condition
       2. No Penicillin Allergy
          1. Penicillin G 1.2 MU IM q4 weeks
          2. Penicillin V 250 mg PO bid
       3. Penicillin Allergic
          1. Erythromycin 500 mg PO qd
          2. Azithromycin 250 mg PO qd
          3. Clarithromycin 500 mg PO qd
15. Complications:
    1. Thrombophlebitis in older patients
    2. Necrotizing Fasciitis
16. References
    1. Gilbert (2002) Sanford Guide, p. 37
    2. Stulberg (2002) Am Fam Physician 66(1):119-24