Cellulitis is a bacterial infection that affects the dermis and the deeper subcutaneous tissues. It is one of the most common conditions seen in the acute medical setting and is usually diagnosed clinically. Cellulitis is most commonly caused by infection with Streptococcus pyogenes or less commonly Staphylcoccus aureus. The majority of cases resolve with oral antibiotics.
Features
Cellulitis of the right lower leg. Note the diffuse erythema and swelling.
The diagnosis of cellulitis is clinical. No further investigations are required in primary care. Bloods and blood cultures may be requested if the patient is admitted and septicaemia is suspected.
The Eron classification system can be used to guide how we manage patients with cellulitis:
| Class | Features |
|---|---|
| I | There are no signs of systemic toxicity and the person has no uncontrolled co-morbidities |
| II | The person is either systemically unwell or systemically well but with a co-morbidity (for example peripheral arterial disease, chronic venous insufficiency, or morbid obesity) which may complicate or delay resolution of infection |
| III | The person has significant systemic upset such as acute confusion, tachycardia, tachypnoea, hypotension, or unstable co-morbidities that may interfere with a response to treatment, or a limb-threatening infection due to vascular compromize |
| IV | The person has sepsis syndrome or a severe life-threatening infection such as necrotizing fasciitis |
They recommend the following that we admit for intravenous antibiotics the following patients:
The following is recommended regarding Eron Class II cellulitis: