Impetigo & Ecthyma (Pediatric)

Definition

Impetigo is a superficial bacterial skin infection, often caused by Staphylococcus aureus or Streptococcus pyogenes, leading to vesicles, pustules, and honey-colored crusts. Ecthyma is a deeper form involving the dermis, causing ulcerative lesions with crusting.

Epidemiology

• Most common in children aged 2–5 years
• Higher prevalence in warm, humid climates
• More common in boys than girls
• Outbreaks often occur in schools and daycare centers
• Accounts for up to 10% of pediatric dermatology consultations in some regions

Etiology

• Staphylococcus aureus (most common cause)
• Streptococcus pyogenes (Group A Streptococcus)
• Minor skin trauma, insect bites, or dermatitis can predispose to infection
• Poor hygiene and crowded living conditions increase risk
• Immunocompromised children may develop more severe or widespread lesions
• Secondary infection of eczema or other skin lesions

Pathophysiology

• Bacterial colonization of superficial skin layers
• Toxin-mediated damage to keratinocytes (e.g., exfoliative toxins in S. aureus)
• Localized inflammation with vesicle and pustule formation
• In ecthyma, infection extends into dermis causing ulceration
• Crusting and healing with or without scarring depending on depth
• Immune response contains infection but may lead to post-inflammatory pigmentation