16th July 2026

Impetigo

Impetigo is a superficial bacterial skin infection that primarily affects young children, though it can occur at any age. It is highly contagious and spreads through direct skin-to-skin contact or contaminated surfaces. The most common causative organisms are Staphylococcus aureus and Streptococcus pyogenes (Group A Streptococcus). 

There are two main forms:

• Non-bullous impetigo (more common): Starts as erythematous macules that evolve into vesicles and pustules, which rupture to form honey-coloured crusts. Lesions typically affect the face.
• Bullous impetigo: Caused by exfoliative toxin-producing S. aureus. It presents with flaccid bullae which rupture, leaving shallow erosions.

Risk factors include poor hygiene, minor skin trauma (e.g. insect bites), eczema or other dermatoses, hot and humid climates, and nasal carriage of S. aureus.

Diagnosis

Diagnosis is clinical. Swabs for culture and sensitivities are reserved for:

• Recurrent or resistant cases
• Widespread infection or suspected MRSA
• Outbreak settings

Management

• Localised, non-bullous impetigo:
  • Hydrogen peroxide 1% cream (first-line)
  • Topical fusidic acid or mupirocin if needed
• Extensive or bullous impetigo:
  • Oral flucloxacillin or clarithromycin

Children should also be excluded from school until lesions are crusted or 48h after antibiotics.