Related Subjects:
|Cellulitis
|Impetigo
|Erysipelas
|Pyoderma gangrenosum
|Pemphigus Vulgaris
|Toxic Epidermal Necrolysis
|Stevens-Johnson Syndrome
|Necrotising fasciitis
|Gas Gangrene (Clostridium perfringens)
|Anatomy of Skin
|Skin Pathology and lesions
|Skin and soft tissue and bone infections
About Erysipelas
- Erysipelas is an acute superficial bacterial skin infection involving the upper dermis and lymphatics.
- It is caused almost exclusively by Group A Streptococcus.
- Typically affects the face or lower limbs and presents with a well-demarcated, raised erythematous rash.
- More common in older adults and those with skin breaks, lymphoedema, or venous insufficiency.
🧬 Aetiology
- Group A Streptococcus: primary pathogen (via skin breach).
- Risk factors: eczema, tinea pedis, ulcers, lymphoedema, obesity, diabetes.
🩺 Clinical Features
- Well-demarcated, raised erythema with a sharply defined edge.
- Warm, tender, swollen skin (often bright red and shiny).
- Systemic features: fever, chills, malaise.
- Lymphangitis and lymphadenopathy may be present.
- Most commonly affects lower limb or face.
Differential Diagnosis
- Cellulitis: deeper, poorly demarcated infection.
- Contact dermatitis: usually pruritic, not systemic.
- Venous eczema: chronic, bilateral, less acute.
- Deep vein thrombosis: unilateral swelling without erythematous border.
🔎 Investigations (NICE)
- Clinical diagnosis – investigations usually not required.
- Blood tests/cultures: only if systemically unwell or immunocompromised.
- Swabs: not routine unless purulent or atypical.
💊 Management (NICE NG141)
- Mild–moderate (oral):
- First-line: Flucloxacillin 5–7 days
- If true penicillin allergy: Clarithromycin or Erythromycin
- If clearly erysipelas (streptococcal):
- Phenoxymethylpenicillin may be used
- Severe/systemically unwell:
- IV flucloxacillin ± broader cover (local guidance)
- Supportive:
- Analgesia (paracetamol/ibuprofen)
- Elevation of affected limb
- Mark margins to monitor spread
🛡️ Prevention
- Treat underlying skin conditions (e.g. tinea pedis, eczema).
- Optimise oedema control (compression if appropriate).
- Recurrent cases: consider prophylactic penicillin V.
📈 Prognosis
- Usually responds well within 48–72 hours of antibiotics.
- Complications: abscess, sepsis, recurrence.
- Recurrence common if risk factors persist.
Erysipelas sits on the superficial end of the cellulitis spectrum, which explains its sharply demarcated edge—lymphatic involvement creates that raised border, unlike deeper cellulitis which spreads diffusely through subcutaneous tissue. The microbiology matters because streptococci remain universally sensitive to penicillin, allowing for narrower-spectrum therapy—this is a key antimicrobial stewardship principle in UK practice. NICE discourages routine investigations because yield is low and management is clinical, unless systemic toxicity suggests bacteraemia. Recurrence is driven less by organism persistence and more by host factors (lymphatic damage, oedema), which is why prevention focuses on addressing these rather than repeated acute treatments.
📚 NICE References
