II. Epidemiology

  1. Age: Children and Elderly

III. Pathophysiology

  1. Ulcerative Bacterial Skin Infection (Pyoderma) occurring at minor Skin Trauma sites
  2. Ecthyma is caused by group A beta-hemolytic streptococcal infection
    1. Contrast with Impetigo which is caused by Streptococcus or Staphylococcus aureus
  3. As with Impetigo, Ecthyma starts as a superficial infection
    1. However unilke Impetigo which remains superficial, Ecthyma extends into the deeper Dermis
    2. Ecthyma, which its involvement of the entire Dermis, results in scarring

IV. Risk Factors

  1. Immunosuppression
  2. Poor hygiene
  3. Overcrowded living conditions
  4. Malnutrition
  5. Humid environments
  6. Previously Traumatized skin

V. Signs

  1. Initial
    1. Small fluid filled Vesicles, Pustules or erythematous Papules
    2. Most commonly form on the legs
  2. Days Later
    1. Lesions ulcerate into coin size depressed Plaques with raw base and surrounding erythema
    2. Lesions are covered in central thick brown-gray adherent crusts and dried marginal exudates
  3. Weeks later
    1. Untreated ulcers heal spontaneously, but often with secondary scar formation

VI. Differential Diagnosis

  1. See Skin Infection
  2. Impetigo
    1. Superficial Skin Infections limited to the Stratum Corneum
    2. Overlying honey colored crusts
  3. Ecthyma Contagiosum (Parapoxvirus, Orf)
    1. Localized viral dermal Skin Infection acquired from animal exposure (cattle, goats, sheep)
  4. Ecthyma Gangrenosum
    1. Large (>3 cm diameter) papular lesions with hemorrhagic crust
    2. Due to hematologic spread of Pseudomonas aeruginosa, in Immunocompromised patients

VII. Management

  1. Use oral Antibiotics with Gram PositiveAntibiotic coverage (e.g. Cephalexin, Dicloxacillin)
    1. See Impetigo for a full list of systemic agents
    2. Topical agents alone are likely to fail due to the full thickness Pyoderma with Ecthyma

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