From the Guidelines
The most likely organism responsible for pediatric impetigo is Staphylococcus aureus, which accounts for the majority of cases, as stated in the guidelines by the Infectious Diseases Society of America 1.
Causative Organisms
- Staphylococcus aureus is the primary causative organism of pediatric impetigo, with Group A beta-hemolytic streptococci (Streptococcus pyogenes) being the second most common cause.
- Both pathogens can be present simultaneously, and the infection can manifest as bullous or nonbullous impetigo, with the former being caused by strains of S. aureus that produce a toxin cleaving the dermal-epidermal junction 1.
Clinical Presentation
- Impetigo typically presents as honey-colored crusted lesions or pustules on the face, particularly around the nose and mouth, or on extremities.
- The infection begins as erythematous papules that rapidly evolve into vesicles and pustules, which rupture and form the characteristic honey-colored crusts on an erythematous base 1.
Treatment
- For treatment, mild cases can be managed with topical antibiotics such as mupirocin 2% ointment applied twice daily for 5 days, as recommended by the guidelines 1.
- More extensive infections may require oral antibiotics, with first-line options including cephalexin or dicloxacillin for 7 days, as outlined in the evidence 1.
- In areas with high MRSA prevalence, clindamycin or trimethoprim-sulfamethoxazole may be more appropriate, considering the potential for resistance 1.
Prevention
- Good hygiene practices, including daily bathing with soap, keeping fingernails short, and avoiding sharing personal items, can help prevent the spread of this highly contagious infection.
- The use of topical or oral antimicrobials, as recommended by the guidelines, can help decrease the transmission of infection, especially in outbreaks affecting several people 1.
From the FDA Drug Label
Mupirocin ointment, 2% is indicated for the topical treatment of impetigo due to: Staphylococcus aureus and Streptococcus pyogenes. The most likely organisms responsible for pediatric impetigo are Staphylococcus aureus and Streptococcus pyogenes 2.
From the Research
Causes of Pediatric Impetigo
- The most likely organisms responsible for pediatric impetigo are Staphylococcus aureus and Streptococcus pyogenes 3, 4, 5, 6, 7.
- Nonbullous impetigo, which accounts for 70% of cases, can be caused by either Staphylococcus aureus or Streptococcus pyogenes 3, 4, 7.
- Bullous impetigo, which accounts for 30% of cases, is caused exclusively by Staphylococcus aureus 3, 4, 7.
- Studies have shown that Staphylococcus aureus is the most frequently isolated pathogen in impetigo cases, especially in nonbullous impetigo 5, 6.
Prevalence of Causative Organisms
- Staphylococcus aureus is present in 80% of nonbullous impetigo lesions and is the only pathogen cultured in 50% of patients 6.
- Group A beta-haemolytic streptococcus is isolated alone in 3% of lesions and in association with S. aureus in 30% of patients 6.
- The rate of resistance among staphylococci responsible for nonbullous impetigo is increasing 6.