ecthyma

Introduction

Variant of impetigo.

• infection of the skin involving the dermis characterized by crusted erosions or ulcerations

Etiology

• contagious ecthyma is caused by orf virus
  • primary infection of superficial break in skin
    • animal bite
• according to ref
  • Streptococcus pyogenes (MKSAP20)
  • Staphylococcus aureus
    • most commonly phage group 2, type 71 same etiologic agent as Staphylococcal scalded skin syndrome
  • primary infection of superficial break in skin
  • secondary infection of pre-exsiting dermatosis
  • predisposing factors
    • colonization of skin by S aureus & S pyogenes
    • warm ambient temperature
    • high humidity
    • neglect

Epidemiology

• persons with diabetes mellitus
• a lesion of neglect, neglected elderly
• develops in excoriations, insect bites, minor trauma indiabetics, elderly patients, soldiers & alcoholics
• may develop in previously well patients

Clinical manifestations

• durations of lesions: weeks to months
• painful rash with purulent-appearing papules
• ulceration with thick, adherent hemorrhagic crust
• lesions round or oval, may be > 3 cm in size (saucer-shaped)
• distribution: ankles, dorsal aspect of feet, thighs, buttocks
  • almost always occur on legs or feet
  • case report shows lesions on hands
• regional lymphadenopathy may be present
• often leaves a scar after healing

* images

Complications

• lymphangitis
• suppurative lymphadenitis
• cellulitis or erysipelas
• septicemia

Differential diagnosis

• Herpetic ulcers
• excoriated insect bite
• neurotic excoriations
• cutaneous diptheria
• porphyria cutanea tarda
• venous stasis
• atherosclerotic ulcers

Management

• contagious ecthyma
  • routine wound care
  • antibiotic agents for possible bacterial superinfection
• topical agents
  • mupirocin (Bactroban) TID to affected skin & to nares for 7-10 days
  • benzoyl peroxide (prevention)
• systemic antibiotics
  • group A streptococcus (S pyogenes)
    • penicillin VK 250 mg PO TID
    • benzathine penicillin
      • 600,000 units IM (< 6 years of age)
      • 1,200,000 units IM (> 6 years of age)
    • erythromycin 250-500 mg PO QID for 10 days
    • cephalexin 250-500 mg QID for 10 days
  • Staphylococcus aureus
    • dicloxacillin 250-500 mg PO QID
    • cephalexin
      • 250-500 mg PO QID for 10 days (adults)
      • 40-50 mg/kg/day for 10 days (children)
    • amoxicillin clavulanate (Augmentin)
      • 20 mg/kg/day divided TID for 10 days
    • macrolides for penicillin-sensitive individuals
      • erythromycin
        • 1-2 g/day divided QID for 10 days (adults)
        • 40 mg/kg/day divided QID for 10 days (children)
      • clarithromycin 250-500 mg PO BID for 10 days
      • azithromycin 250 mg QD for 5-7 days
    • clindamycin
      • 150-300 mg QID for 10 days (adults)
      • 15 mg/kg/day divided QID for 10 days (children)
  • methicillin-resistant Staphylococcus aureus (MRSA)
    • mupirocin ointment
    • minocycline 100 mg PO BID for 10 days
    • Bactrim DS 1-2 tabs QD
    • ciprofloxacin 500 mg PO BID

More general terms

• skin disease (dermatologic disorder, dermatopathy, dermatosis)

More specific terms

• ecthyma gangrenosum