Cellulitis
- Cellulitis is a spreading infection in the subcutaneous tissue
- Often occurs after skin abrasion or other similar trauma
- Usually due to infection with ß haemolytic streptococcus or Staph. aureus
- Both produce enzymes that degrade tissue and allow spread of infection
Clinical features
- Cellulitis usually presents with a well demarcated area of inflammation
- Redness, heat, swelling and pain are the cardinal signs of inflammation
Picture provided by Peter Devitt, Royal Adelaide Hospital, South Australia
- Usually associated with malaise, fever and a raised white cell count
- If not rapidly treated it can progress to lymphangitis and lymphadenitis
- Localised areas of skin necrosis may occur
- Predisposing factors include
- Lymphoedema
- Venous stasis
- Diabetes mellitus
- Surgical wounds
Management
- Rest and elevation of the affected limb
- Antibiotics
- May initially be given orally
- Intravenous administration if no rapid improvement
- Benzylpenicillin and flucloxacillin are usually antibiotics of choice
Necrotising soft tissue infections
- Are the result of skin and subcutaneous infections with virulent bacteria
- Toxins can cause widespread skin and fascial necrosis
Melaney's synergistic gangrene
- This results from synergistic infection affecting principally the skin
- Usually occurs around surgical wounds, stomas and cutaneous fistulae
- Due to infection with both Staph. aureus and anaerobic streptococci
- Often initially indistinguishable from cellulitis
- Spreads slowly and often results in skin ulceration
- Lacks the severe systemic toxicity seen with necrotising fascitis
Management
- Antibiotics including benzylpenicillin
- Surgical debridement of the affected area
Necrotising fascitis
- Occurs in immunocompromised patients
- Often diabetic, alcoholics or intravenous drug abusers
- Occurs at several characteristic sites
- Limbs after cuts, abrasions or bites
- Around postoperative abdominal surgical wounds
- In the perineum secondary to anorectal sepsis
- In the male genitalia (Fournier's gangrene)
- Polymicrobial infection involving the following:
- Facultative aerobes
- Streptococcal species or E. coli
- Anaerobes
- Exotoxins produce severe systemic toxicity
Clinical features
- Often presents similar to cellulitis
- Warning features include
- Severe pain - out of proportion to the clinical signs
- Severe systemic toxicity
- Cutaneous gangrene
- Hemorrhagic fluid leaking from a wound
- Untreated it progresses to multiple organ failure
- Overall has about a 30% mortality
- X-ray may show gas in the subcutaneous tissue
Management
- Requires high clinical suspicion and early diagnosis
- Patients should be managed in high dependency unit
- Need fluid resuscitation and organ support
- Early surgical debridement is essential
- Requires excision well into apparently normal tissue
- Amputation or fasciotomies may be required
- Defunctioning colostomy may be required for perineal sepsis
- Antibiotic cover should include benzylpenicillin, metronidazole and gentamycin
- Hyperbaric oxygen therapy may be of benefit
Bibliography
Bisno A L, Stevens D L. Streptococcal infections of skin and soft tissues. N Engl J Med
1996; 334: 240-245.
Burge T S, Watson J D. Necrotising fascitis. be bloody, bold and resolute. Br Med
J 1994; 308: 1453-1454.
Green R J, Dafoe D C, Raffin T A. Necrotising fascitis. Chest 1996;
110: 219-229.
Lewis R T. Soft tissue infections. World J Surg 1998; 22: 146-151.
Swartz N M. Cellulitis. N Engl J Med 2004; 350: 904-912.
Xeropotamos N S, Nousias V E, Kappas A M. Fournier's gangrene: diagnostic approach an
therapeutic challenge. Eur J Surg 2002; 168: 91-95. |