What causes noma?

Causes of Noma (Cancrum Oris)

Noma is primarily caused by a combination of severe malnutrition, poor oral hygiene, and opportunistic polymicrobial infection, often occurring in the context of concurrent debilitating diseases in vulnerable children. 1, 2

Primary Causative Factors

• Malnutrition: Protein-energy malnutrition and vitamin deficiencies are fundamental factors that make the oral mucosa susceptible to opportunistic pathogens 3
• Poor oral hygiene: Inadequate oral hygiene allows bacterial proliferation and is a key predisposing factor for noma development 2, 3
• Polymicrobial infection: Noma involves opportunistic bacterial infections with multiple species including:
  • Fusobacterium necrophorum
  • Prevotella intermedia
  • Prevotella melaninogenica
  • Fusobacterium nucleatum
  • Bacteroides fragilis
  • Bacillus cereus
  • Trueperella pyogenes
  • Various spirochetes 2

Predisposing Conditions and Risk Factors

• Concurrent infectious diseases that compromise immunity:
  • Measles
  • Malaria
  • HIV infection 1
• Compromised immune system from any cause 4
• Preceding oral conditions:
  • Acute necrotizing gingivitis
  • Stomatitis
  • Lesions of the gingival mucosal barrier 1, 4
• Socioeconomic factors:
  • Extreme poverty
  • Limited access to healthcare
  • Food insecurity 1, 5

Pathophysiological Mechanism

• Noma begins as an intraoral lesion in the gingival-oral mucosa complex 5
• The disease process typically follows this progression:
  1. Initial gingival inflammation or mucosal lesion
  2. Opportunistic bacterial invasion of compromised tissues
  3. Rapid spread of gangrenous infection
  4. Extensive facial tissue destruction involving both soft and hard tissues 2, 5
• The disease is non-contagious despite its infectious nature 1
• Current research suggests an imbalance in normal intraoral microorganisms rather than introduction of a specific pathogen 1

Epidemiological Context

• Noma primarily affects malnourished children in developing countries, particularly in sub-Saharan Africa 1, 5
• Global annual incidence is estimated at 30,000-40,000 cases 1
• Mortality rate approaches 85% without treatment 1
• The disease has been virtually eliminated in developed countries but persists in regions with high poverty rates 2

Prevention Strategies

• Addressing food security and malnutrition 1
• Improving access to vaccinations, particularly measles 1
• Prevention and treatment of malaria and HIV 1
• Early detection and treatment of necrotizing gingivitis and stomatitis 1
• Promotion of good oral hygiene practices 3
• Training healthcare workers to improve diagnosis and treatment of oral infections 3

Understanding these multifactorial causes is essential for developing effective prevention strategies and ultimately working toward global eradication of this devastating but preventable disease.