16th July 2026

Cellulitis

Cellulitis is an acute infection involving the deep dermis and subcutaneous tissues. It typically presents with localised pain, erythema, warmth, and swelling, often with systemic signs like fever.

The most common pathogens are Streptococcus pyogenes and Staphylococcus aureus. Risk factors include diabetes, peripheral vascular disease, venous insufficiency, tinea pedis, and obesity.

Diagnosis

Diagnosis is clinical. Imaging may be considered if an abscess or necrotising fasciitis is suspected. Differentials include DVT, contact dermatitis, erysipelas, and stasis dermatitis.

Management

• Mild: oral flucloxacillin
• Severe or systemically unwell: IV flucloxacillin, consider MRSA cover if risk factors present
• Treat underlying risk factors