Erysipelas and Cellulitis

Erysipelas and Cellulitis - Red Alert Skin

-   Erysipelas: Predominantly Group A Streptococcus (GAS).
-   Cellulitis: *Staphylococcus aureus* (including MRSA), GAS; less commonly *H. influenzae* (children, facial), *Pseudomonas* (hot tubs, puncture wounds).

• Risk Factors:
  • Skin barrier disruption (trauma, ulcers, tinea pedis).
  • Lymphedema, venous insufficiency.
  • Obesity, diabetes mellitus, immunosuppression.

⭐ Erysipelas classically involves the face (butterfly rash) or lower limbs, with a sharply defined, raised, indurated, and often tender border.

Erysipelas and Cellulitis - Spotting the Spread

• Clinical Features (Local):
  • Erythema, warmth, swelling, pain/tenderness.
  • Erysipelas: Raised, sharply demarcated, indurated border; often

Erysipelas and Cellulitis - Fighting the Fire

• General Measures:

  • Elevation of affected limb
  • Analgesia (e.g., NSAIDs, Paracetamol)
  • Hydration
  • Marking advancing edges of erythema

• Antibiotic Therapy (Empirical):

  • Non-purulent (Target Streptococci +/- MSSA):
    • Oral: Penicillin V 500mg QID, Amoxicillin 500mg TID, Cephalexin 500mg QID, Flucloxacillin 500mg QID.
    • IV (severe/failed oral): Benzylpenicillin, Cefazolin, Ceftriaxone.
  • Consider MRSA coverage (purulent, severe, risk factors):
    • Oral: Clindamycin 300-450mg QID, Doxycycline 100mg BID, TMP-SMX.
    • IV: Vancomycin, Linezolid, Daptomycin.

⭐ For non-purulent cellulitis/erysipelas, empirical therapy should primarily target Streptococci (e.g., Penicillin, Amoxicillin, Cephalexin). If MRSA is suspected or prevalent (e.g. purulent cellulitis, severe infection, specific risk factors), add coverage with Clindamycin, Doxycycline, or TMP-SMX.

Erysipelas and Cellulitis - Danger Zones & Defenses

Complications:

• Abscess, bullae formation
• Necrotizing fasciitis (⚠️ severe)
• Sepsis, osteomyelitis
• Post-streptococcal glomerulonephritis (rare with skin)
• Chronic lymphedema (sequela & risk factor)

Recurrence & Prevention:

• Address predisposing factors:
  • Lymphedema, venous insufficiency (e.g., compression)
  • Obesity (weight management)
  • Tinea pedis (treat fungal infections)
  • Skin breaks (wound care, hygiene)
• Consider long-term prophylactic antibiotics for ≥2 episodes/year.

⭐ Recurrent erysipelas/cellulitis is common (up to 50% in 3 years), especially with underlying risk factors like lymphedema, venous insufficiency, obesity, and tinea pedis; long-term prophylactic antibiotics may be considered in such cases (e.g., Penicillin V or erythromycin).

High‑Yield Points - ⚡ Biggest Takeaways

• Erysipelas: Superficial dermal infection, sharply demarcated raised "peau d'orange" texture, mainly S. pyogenes.
• Cellulitis: Deeper dermis/subcutaneous infection, indistinct borders, S. aureus or S. pyogenes.
• Erysipelas ("St. Anthony's fire") often on face or legs; Milian's ear sign is characteristic.
• Non-purulent cellulitis suggests Streptococci; purulent (abscess) points to Staphylococci (often MRSA).
• Key distinction: Depth of inflammation and border definition (sharp vs. diffuse).
• Risk factors for cellulitis: Skin breaks, lymphedema, venous insufficiency.