Erysipelas

By Dr. Pascal Bafteh · last updated 09/2026

In-depth: Clinically Important Facts on Pyodermas

Staphylococcus aureus — Exfoliative Toxins

• ETA and ETB are serine proteases that cleave Desmoglein-1 → intraepidermal cleavage (same mechanism as Pemphigus foliaceus).

Ecthyma

• Risk Factors: Typical risks are DM + HIV + CVI, poor hygiene, and entry points (prurigo, scabies).
• Pathogens: Frequently Strep. + Staph. + Pseudomonas.
• Complication: Post-streptococcal glomerulonephritis.

SSSS (Staphylococcal Scalded Skin Syndrome)

• Clinical Presentation: widespread erythema with Nikolsky-positive erosions, on the back due to sweat, DD-relevant to TEN (Histology: SSSS subcorneal, TEN dermo-epidermal!).
• Entry Point: Mostly Otitis media or pharyngitis with toxin-producing S. aureus.

Cellulitis vs. Erysipelas vs. Phlegmon vs. Necrotizing Fasciitis

NF = Necrotizing Fasciitis · “Cellulitis” is the Anglo-American term, in German usage it largely overlaps with Phlegmone.

• Erysipelas Spread Direction: Typically distal to proximal via the lymphatic vessels.
• Facial Erysipelas: First choice — also on the face — is Penicillin G (or V); if response is insufficient or entry point suggests S. aureus, add Flucloxacillin or Amoxicillin/clavulanate.
• Erysipelas with a reported penicillin allergy: First sharpen the history: most reported "penicillin allergies" are not a true immediate-type allergy (rash during a viral infection, GI upset, a vague childhood label). With a mild, non-immediate reaction in the history a cephalosporin (e.g. cefazolin or cefuroxime) may be given — cross-reactivity of modern cephalosporins with penicillins is far below the historically quoted 10 % and depends mainly on similarity of the side chain rather than on the beta-lactam ring itself. With a true immediate reaction (urticaria, angioedema, anaphylaxis) or a severe cutaneous adverse reaction (SJS/TEN, DRESS), beta-lactams are avoided: the standard alternative is clindamycin, which additionally inhibits toxin synthesis at the 50S ribosome — alternatively macrolides (mind resistance rates), and linezolid or vancomycin in severe disease. After recovery, offer allergy testing and correct the allergy passport; unnecessary beta-lactam avoidance demonstrably worsens the quality of treatment.
• Erysipelas Recurrence Risk: 6 months ~ 10%, 3 years ~ 30%.

Necrotizing Fasciitis — Special Forms

• Fournier's Gangrene: Defined as genitoanal necrotizing fasciitis with fulminant polymicrobial course (E. coli + anaerobes + enterococci).
• Phlegmasia coerulea dolens: Characteristic is a fulminant venous blockade with livid leg + shock — emergency and important DD to necrotizing fasciitis.

Recurrent Streptococcal Perineal Dermatitis (Children)

• Clinical Presentation: sharply demarcated, bright red anogenital erythema in children, often with pruritus and painful defecation.

Differential diagnoses

• Phlegmon
• Erysipeloid
• Urticaria
• Angioedema
• Allergic contact dermatitis
• Herpes zoster
• Lupus Pernio (Sarcoidosis)
• Rosacea fulminans / Pyoderma faciale

Sources (selection)

1. Plewig 2018 Braun-Falco p.156

More bacterial skin infections

• Erythema migrans (Lyme disease)
• Erythrasma
• Lepromatous leprosy
• Sporotrichosis

Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.