Background
- Infection of the (upper) dermis and subcutaneous tissue
- Superficial (involving just the upper tissues) is also known as Erysipelas (although it is often clinically very difficult to differentiate)
- One way is that cellulitis tends to have poorly demarcated borders c.f. erysipelas
- Superficial (involving just the upper tissues) is also known as Erysipelas (although it is often clinically very difficult to differentiate)
Aetiology/Risk factors
- Risk factors include
- Previous cellulitis
- Venous disease e.g. venous eczema, venous ulcers; and/or lymphoedema
- Current/prior injury e.g. trauma, surgery, radiotherapy
- Diabetes, alcoholism, obesity
- Pregnancy
- Fungal infection (between toes)
- Concomitant skin disease
- Most cases are caused by beta-haemolytic streptococcus e.g. Streptococcus pyogenes (2/3 cases) or by Staph aureus
- Rarer causes include Pseudomonas aeruginosa (puncture wounds); H Influenzae (children with facial cellulitis); Anaerobes (from human bites); Pasteurella multocida (cat/dog bites)
Presentation
- Classically acute onset red, painful, hot, swollen and tender skin.
- Can spread rapidly
- Almost always unilateral
- There may be evidence of a break in the skin (or other source of infection)
- Other symptoms include fever, malaise, nausea, shivering and rigors
- The patient may also have evidence of sepsis e.g. tachycardia, tachypnoeia, confusion, hypotension etc
Investigations
- Usually a clinical diagnosis (start treatment before cultures/sensitivity)
- In patients who present atypically, swabs/cultures from entry sites or broken/weeping skin may be useful
- In patients where other causes e.g. DVT, might be possible, appropriate investigations should be performed e.g. D-Dimers, USS
Management
- Antibiotic treatment
- If in the community- 1g Flucloxacillin four times daily for 7 days (Doxycycline in penicillin allergic or risk of MRSA)
- If the patient is Septic, patients should be referred to hospital for IV Flucloxacillin 1g QDS (increase to 2g if BMI>30)
- IVOST when appropriate
- if penicillin allergic, IV vancomycin can be used
- If the patient is in severe sepsis and/or has Necrotising Fasciitis
- Refer to HDU and give IV Flucloxacillin (2g QDS) + Clindamycin (1.2g QDS) + Gentamycin (7mg/kg as per protocol)
- Omit flucloxacillin if allergic and add vancomycin if suspected MRSA infection