(Infection)

Overview

• Infection of the deep dermis and subcutaneous tissue
• Develops when micro-organisms gain entry to the dermal and subcutaneous tissues via disruptions in the cutaneous barrier (eg. minor skin injury)
• Most common causative bacteria are Streptococcus pyogenes (catalase -ve) and Staphylococcus aureus (catalse +ve)
• Risk Factors → diabetes, venous insufficiency, eczema, oedema, obesity

Making Diagnosis

Clinical Features:

• Acute onset of red, painful, hot, swollen skin
• Poorly defined (not well demarcated) lesions
  • Erysipelas → causes well defined lesion. More superficial, limited verision of cellulitis. Caused by streptococcus pyogenes.
• Most commonly occurs on the legs (shins)
• Systemic Symptoms → fever, chills, nausea, headache

(Look at Obs ⇒ consider sepsis). Septic Signs → high HR, high RR, low BP, confusion (low GCS).

Investigations:

• Clinical Diagnosis → only request further tests if signs of systemic illness or septicaemia