What is the most common cause (MCC) of impetigo in a 4-year-old?

From the Guidelines

The most common cause (MCC) of impetigo in a 4-year-old child is Staphylococcus aureus, followed by group A beta-hemolytic streptococci (Streptococcus pyogenes) 1. These bacteria typically enter through breaks in the skin and cause the characteristic honey-colored crusted lesions or bullous lesions.

Key Points to Consider

• Impetigo is a highly contagious skin infection that requires prompt treatment to prevent spread and reduce the risk of complications.
• The diagnosis of impetigo is typically made based on clinical presentation, with laboratory tests such as Gram stain and culture recommended to help identify the causative organism 1.
• Treatment of impetigo depends on the severity and extent of the infection, with topical antibiotics such as mupirocin or retapamulin recommended for localized infections, and oral antibiotics such as cephalexin or clindamycin recommended for more extensive infections 1.

Treatment Options

• Topical mupirocin (Bactroban) 2% ointment applied twice daily for 5 days is a recommended first-line therapy for localized impetigo with few lesions 1.
• Oral cephalexin (25-50 mg/kg/day divided into 4 doses) or clindamycin (20 mg/kg/day divided into 3 doses) for 7 days is recommended for more extensive impetigo 1.
• In areas with high MRSA prevalence, consider trimethoprim-sulfamethoxazole or clindamycin 1.

Prevention and Control

• Good hygiene practices are essential to prevent spread, including daily bathing with antibacterial soap, keeping fingernails short, and avoiding sharing personal items.
• Parents should be advised that the infection is contagious until 24-48 hours after starting antibiotics, and children should not return to school or daycare until this period has passed.

From the FDA Drug Label

INDICATIONS AND USAGE Mupirocin ointment, 2% is indicated for the topical treatment of impetigo due to: Staphylococcus aureus and Streptococcus pyogenes. The most common causes (MCC) of impetigo in a 4-year-old are:

• Staphylococcus aureus
• Streptococcus pyogenes 2

From the Research

Most Common Cause of Impetigo

• The most common cause of impetigo in children is Staphylococcus aureus or Streptococcus pyogenes 3, 4, 5, 6, 7

Types of Impetigo

• There are two principal types of impetigo: nonbullous (70% of cases) and bullous (30% of cases) 3, 4, 5, 6

Characteristics of Nonbullous Impetigo

• Nonbullous impetigo is characterized by honey-colored crusts on the face and extremities 3, 4, 6

Characteristics of Bullous Impetigo

• Bullous impetigo results in large, flaccid bullae and is more likely to affect intertriginous areas 3, 4, 5, 6

Treatment of Impetigo

• Treatment includes topical antibiotics such as mupirocin, retapamulin, and fusidic acid 3, 5, 6
• Oral antibiotic therapy can be used for impetigo with large bullae or when topical therapy is impractical 3, 5, 6, 7
• Amoxicillin/clavulanate, dicloxacillin, cephalexin, clindamycin, doxycycline, minocycline, trimethoprim/sulfamethoxazole, and macrolides are options, but penicillin is not 3, 7