Chapter 116. Impetigo

A young woman presented to the office with a 3-day history of an uncomfortable rash on her lip and chin (Figure 116-1). She denied any trauma or previous history of oral herpes. This case of impetigo resolved quickly with oral cephalexin.

An 11-year-old-child presented with a 5-day history of a skin lesion that started after a hiking trip (Figure 116-2). This episode of bullous impetigo was found to be secondary to methicillin-resistant Staphylococcus aureus (MRSA). The lesion was rapidly progressive and was developing a surrounding cellulitis. She was admitted to a hospital and treated with intravenous clindamycin with good results.1

Impetigo is the most superficial of bacterial skin infections. It causes honey crusts, bullae, and erosions.

• Most frequent in children ages 2 to 6 years, but it can be seen in patients of any age.
• Common among homeless people living on the streets.
  • Seen often in third world countries in persons living without easy access to clean water and soap.
• Contagious and can be spread within a household.

• Impetigo is caused by S. aureus and/or group A β-hemolytic Streptococcus (GABHS).
• Bullous impetigo is almost always caused by S. aureus and is less common than the typical crusted impetigo.
• Impetigo may occur after minor skin injury, such as an insect bite, abrasion, or dermatitis.

Clinical Features

• Vesicles, pustules, honey-colored (Figure 116-1), brown or dark crusts, erythematous erosions (Figure 116-3), ulcers in ecthyma (Figure 116-4), bullae in bullous impetigo (Figures 116-5, 116-6, 116-7).