Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!

Patient Story

A 4-year-old child presents with a fever and a red and swollen foot (Figure 103-1). The patient injured her foot 3 days before with a door. On physical examination, the foot was warm, tender, red, and swollen, and the child’s temperature was 39.4°C (103°F). This is classic cellulitis and the child was admitted for IV antibiotics.

FIGURE 103-1

Cellulitis of the foot after an injury with a door in a 4-year-old girl. (Used with permission from Richard P. Usatine, MD.)


Cellulitis is an acute infection of the skin that involves the dermis and subcutaneous tissues.


  • In one review of serious skin infections in children admitted to a hospital in New Zealand, the most common types of infection were cellulitis (38%) and subcutaneous abscesses (36%).1 The most frequent sites of infection were the head, face and neck, (32%) and lower limbs (32%). The most frequently isolated organisms were Staphylococcus aureus (48%) and Streptococcus pyogenes (20%).1

  • Facial cellulitis occurs more often in children ages 6 months to 3 years.

  • Perianal cellulitis occurs more commonly in young children (see Chapter 95, Diaper Rash and Perianal Dermatitis).

Etiology and Pathophysiology

  • Often begins with a break in the skin caused by trauma, a bite, or an underlying dermatosis (e.g., atopic dermatitis) (Figures 103-1 to 103-4).

  • Is most often caused by group A β-hemolytic Streptococcus (GAS) (Figure 103-3) or Staphylococcus aureus. The most common etiology of cellulitis with intact skin, when it has been determined through needle aspiration and/or punch biopsy, is S. aureus, outnumbering GAS by a ratio of nearly 2:1.2

  • There are increasing concerns about the role of community-acquired methicillin-resistant S. aureus (MRSA) in all soft-tissue infections including cellulitis.36

  • After a cat or dog bite, cellulitis is often caused by Pasteurella multocida (Figure 103-4).

  • After saltwater exposure, cellulitis can be secondary to Vibrio vulnificus in warm climates. A Vibrio vulnificus infection can be especially deadly.

  • Erysipelas is a specific type of superficial cellulitis with prominent lymphatic involvement and leading to a sharply defined and elevated border (Figures 103-5 and 103-6).

  • Risk factors for hospitalization for staphylococcal skin infections in children in California were age less than 3 years, being Black, and lacking private insurance.7

FIGURE 103-2

Cellulitis at the site of a clenched-fist injury when a young man hit another person on the tooth during a fight. This can result in a septic joint as well as a septic tenosynovitis. (Used with permission from Richard P. Usatine, MD.)

FIGURE 103-3

Group A β-hemolytic Streptococcus (GAS) cellulitis ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.