Potential Complications of Untreated Impetigo
Untreated impetigo can lead to serious complications including post-streptococcal glomerulonephritis, sepsis, and progression to deeper tissue infections, with children being particularly vulnerable to these outcomes. 1, 2
Common Complications
Immediate Local Complications
- Spread of infection: Impetigo is highly contagious and can spread to other parts of the body or to other individuals through direct contact 1
- Progression to deeper tissues: What begins as a superficial infection can extend below the dermis to involve subcutaneous tissue, fascial planes, or muscular compartments 3
- Regional lymphadenitis: Enlargement and inflammation of regional lymph nodes may occur as the infection spreads 1
Systemic Complications
- Post-streptococcal glomerulonephritis: The most serious complication of streptococcal impetigo, affecting the kidneys 2
- Sepsis syndrome: In severe cases, especially in immunocompromised patients, the infection can progress to systemic inflammatory response and sepsis 3
- Bacteremia: Particularly in bullous impetigo, the toxin-producing strains of S. aureus can enter the bloodstream 4
Risk Factors for Complications
Certain factors increase the risk of developing complications:
- Age: Children under 5 years and especially neonates are at higher risk 4
- Host factors: 3
- Advanced age (≥75 years)
- Malnutrition
- Diabetes
- Smoking
- Obesity
- Prolonged hospitalization
- Immunocompromised status
Progression to More Severe Infections
Untreated impetigo can evolve into more serious conditions:
- Cellulitis: Infection spreading to deeper layers of the skin 3
- Ecthyma: A deeper form of impetigo that extends into the dermis 5
- Staphylococcal scalded skin syndrome (SSSS): Particularly in infants and young children, bullous impetigo can progress to this more severe condition with widespread blistering and skin exfoliation 4
- Invasive infections: In rare cases, progression to fasciitis or myonecrosis requiring aggressive surgical debridement 3
Special Considerations
- Antibiotic resistance: Increasing prevalence of resistant bacteria (MRSA, macrolide-resistant streptococcus) can complicate treatment of advanced infections 2
- Recurrent infections: Untreated impetigo can lead to cycles of reinfection, particularly when there are asymptomatic nasal carriers of S. aureus in the household 4
- School/daycare outbreaks: Untreated cases can lead to widespread outbreaks in childcare settings 1
Prevention of Complications
To prevent complications, early intervention is essential:
- Prompt treatment: Initiate appropriate antimicrobial therapy within 24-48 hours of symptom onset 1
- Proper hygiene: Maintain good hygiene practices and avoid sharing personal items 1
- Isolation: Keep infected individuals isolated until at least 24 hours after starting treatment 1
- Carrier identification: Identify and treat asymptomatic nasal carriers in outbreak settings 4
Early recognition and appropriate treatment of impetigo significantly reduces the risk of these potentially serious complications, especially in vulnerable populations such as young children and the immunocompromised.