Skin and Soft Tissue Infections



Cellulitis is an infection of the skin and the soft tissues underneath. The skin forms a physical barrier between the environment and soft tissues. When a patient presents with cellulitis, look for a breach in the skin barrier and a point of entry for the bacteria. This may be due to skin trauma, eczema, fungal nail infections or ulcers. 

Presentation

Skin changes in cellulitis include:

  • Erythema (red discolouration)
  • Warm or hot to touch
  • Tense
  • Thickened
  • Oedematous
  • Bullae (fluid-filled blisters)
  • A golden-yellow crust indicates a Staphylococcus aureus infection

 

Patients may be systemically unwell, including having sepsis.

Causes

The most common causes are:

  • Staphylococcus aureus
  • Group A streptococcus (mainly streptococcus pyogenes)
  • Group C streptococcus (mainly streptococcus dysgalactiae)

 

MRSA should be considered, particularly in patients the repeated hospital admissions and antibiotics.

Eron Classification

The Eron classification assesses the severity of cellulitis:

  • Class 1 – no systemic toxicity or comorbidity
  • Class 2 – systemic toxicity or comorbidity
  • Class 3 – significant systemic toxicity or significant comorbidity
  • Class 4 – sepsis or life-threatening infection

 

Management

Class 3 and 4 cellulitis requires admission for intravenous antibiotics. Admission is also considered for frail, very young or immunocompromised patients and those with facial, periorbital or orbital cellulitis. 

Flucloxacillin is the usual first-line antibiotic for cellulitis, either oral or intravenous. It is particularly effective against Staphylococcus aureus and also works well against other gram-positive cocci.

Alternatives:

  • Clarithromycin
  • Clindamycin
  • Co-amoxiclav (the usual first choice for cellulitis near the eyes or nose)

 

Last updated July 2023