Cellulitis and Erysipelas

Cellulitis is an acute inflammation of the skin involving the dermis and subcutaneous tissues, caused mainly by
streptococci and staphylococci. Erysipelas has a raised demarcated border, where as the border is not distinct in


  • Streptococcus and S. Aureus in adults
  • Haemophilus influenza type b in children under 3 years
  • Cellulitis is sometimes caused by other organisms

Predisposing factors

  • Minor trauma
  • Pre-existing lesion such as ulcer or erosion

Clinical features

  • Erythema (reddening)
  • Pain, tenderness
  • Acute localised swelling and oedema
  • In erysipelas, lesions are more superficial and have a defined raised margin
  • Skin becomes tense and shiny in advanced stages
  • Regional lymphadentiis may be present

Differential diagnosis

  • Lymphoedema
  • Acute osteomyelitis
  • Deep vein thrombosis (DVT)
  • Blunt trauma/fracture


  • Pus swab for Gram staining and culture and sensitivity


  • Elevate the affected limb
  • Give an analgesic e.g. paracetamol 1 g every 6-8 hours as required, Child: 10 mg/kg
  • Antibiotics: cloxacillin 250-500 mg every 6 hours before food for 7 days
    Child: 12.5-25 mg/kg per dose
  • OR in penicillin allergy, erythromycin 500 mg every 6 hours
    Child: 7.5 mg/kg per dose

If severe

  • IV ceftriaxone Adult: 1 g every 12 hours for 3 days
    Child: 50 mg/kg
  • Then oral antibiotics to complete 1 week of antibiotics