What causes aphthous ulcers?

Causes of Aphthous Ulcers

Aphthous ulcers are primarily caused by a combination of immune system dysfunction, genetic predisposition, and various triggering factors, though the exact etiology remains incompletely understood. 1

Primary Etiological Factors

Immune System Dysfunction

• Disturbances in both innate and acquired immunity play a central role in aphthous ulcer development 2
• Autoimmune or hypersensitivity mechanisms are widely considered as possible pathogenic pathways 3
• Immune response modification appears to be the common pathway through which various triggers operate 2

Genetic Predisposition

• Several precipitating factors appear to operate primarily in individuals with genetic susceptibility 3
• Family history is often positive in patients with recurrent aphthous stomatitis (RAS)

Common Triggering Factors

Nutritional Factors

• Vitamin deficiencies (particularly B vitamins, folate)
• Mineral deficiencies (especially iron)
• Food allergies or sensitivities 2

Systemic Conditions

• Gastrointestinal disorders:
  • Celiac disease
  • Inflammatory bowel disease (Crohn's disease, ulcerative colitis) 2, 1
  • These conditions can present with aphthous-like ulcers as manifestations of systemic disease 4

Immune System Disorders

• HIV infection
• Neutropenia
• Behçet's disease (characterized by recurrent bipolar aphthosis) 4

Local Factors

• Physical trauma to oral mucosa (may trigger ulcers in susceptible individuals) 5
• Mechanical injuries 2
• Local stress to tissues

Other Contributing Factors

• Psychological stress 2
• Hormonal disturbances 2
• Certain viral and bacterial infections 2

Clinical Presentation Types

Three main clinical forms have been described 4:

1. Minor aphthous ulcers - Most common (80-90% of cases)

   • Less than 10mm in diameter
   • Heal within 7-10 days without scarring 5

2. Major aphthous ulcers - More severe form (10% of cases)

   • Larger than 10mm in diameter
   • Can cause scarring 5

3. Herpetiform aphthous ulcers - Multiple small clustered ulcers 4

Diagnostic Approach

When evaluating aphthous ulcers, it's crucial to:

• Determine whether they are idiopathic or manifestations of systemic disease 1
• Assess for well-recognized causes that may be contributing to the disease 3
• Consider differential diagnoses including:
  • Trauma-related ulcers
  • Infectious causes (bacterial, fungal)
  • Drug-induced ulcers
  • Malignant lesions (any solitary chronic ulcer should be biopsied) 4

Management Considerations

Treatment should focus on:

• Identifying and addressing underlying causes when present
• Symptom management with topical treatments (antimicrobial mouthwashes, topical corticosteroids) as first-line therapy 3
• Systemic medications when topical therapy is ineffective 3

The most effective treatments involve agents that suppress or modulate immune system function, with topical agents preferred due to fewer side effects 6.

Common Pitfalls to Avoid

• Failing to investigate for underlying systemic conditions in cases of recurrent or severe aphthous ulcers
• Misdiagnosing other oral ulcerative conditions as simple aphthous ulcers
• Not addressing nutritional deficiencies that may be contributing factors
• Inadequate pain management during acute episodes

When aphthous ulcers are recurrent (defined as at least 4 episodes per year), a more thorough investigation for underlying causes is warranted 4.