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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.

Figure 116-1

Typical honey-crusted plaque on the lip of an adult with impetigo. (Courtesy of Richard P. Usatine, MD.)

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

Figure 116-2

Bullous impetigo secondary to methicillin-resistant Staphylococcus aureus (MRSA) on the leg of an 11-year-old child. Note the surrounding cellulitis. (With permission from Studdiford J, Stonehouse A. Bullous eruption on the posterior thigh 1. J Fam Pract. 2005;54:1041-1044. Reproduced with permission from Frontline Medical Communications.)

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

Figure 116-3

Widespread impetigo with honey-crusted erythematous lesions on the back of a 7-year-old child. (Courtesy of Richard P. Usatine, MD.)

Figure 116-4

Impetigo on the face and hand of a homeless man. Note the ecthyma (ulcerated impetigo) on the dorsum of the hand. (Courtesy of Richard P. Usatine, MD.)

Figure 116-5

Bullous impetigo around the mouth of a young boy that progressed to desquamation of the skin on his hands and feet. (...

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