Causes of Mouth Ulcers
Mouth ulcers are caused by a combination of local and systemic factors including trauma, infections, allergic reactions, autoimmune conditions, nutritional deficiencies, and stress, with many cases involving multiple contributing factors. 1
Common Causes of Oral Ulcers
Local Factors
- Mechanical trauma from sharp edges of teeth, dental appliances, or accidental biting 1
- Physical trauma such as thermal burns 1
- Chemical injuries from strong acids or alkalis 1
- Local infections (bacterial, viral, fungal) 2, 3
Systemic Factors
- Nutritional deficiencies, particularly:
- Immune disorders and autoimmune conditions 1, 2
- Genetic predisposition 1
- Stress and anxiety 1, 6
- Hormonal changes 2
Specific Types of Oral Ulcers
Recurrent Aphthous Stomatitis (RAS)
- Most common type of oral ulceration, affecting up to 25% of the population 6
- Characterized by well-demarcated, oval or round ulcers with white/yellow pseudomembrane and erythematous halo 1
- Likely caused by a combination of:
Disease-Associated Ulcers
- Gastrointestinal disorders (celiac disease, inflammatory bowel disease) 2
- Behçet's syndrome (characterized by recurrent bipolar aphthosis) 2
- Blood disorders (anemia, leukemia) 1, 7
- HIV infection 7, 6
- Bullous diseases (pemphigus, pemphigoid) 3
- Erythema multiforme 2, 3
Malignant Ulcers
- Squamous cell carcinoma may present as persistent oral ulceration 2
- Any solitary chronic ulcer should be biopsied to rule out malignancy 2
Diagnostic Considerations
When to Suspect Systemic Causes
- Ulcers persisting for more than 2 weeks 8, 7
- Ulcers not responding to 1-2 weeks of treatment 1, 7
- Multiple, recurrent, or unusually large ulcers 7
- Ulcers accompanied by systemic symptoms (fever, weight loss, joint pain) 7
Important Diagnostic Tests
- Full blood count to screen for anemia, leukemia, and other blood disorders 1, 7
- Nutritional deficiency screening (iron, folate, vitamin B12) 7, 4
- Fasting blood glucose to identify hyperglycemia, which can predispose to fungal infections 1, 7
- HIV antibody and syphilis serology testing 1, 7
- Biopsy for persistent ulcers or suspected malignancy 8, 7
Common Pitfalls
- Overlooking systemic causes of recurrent oral ulcers can lead to delayed diagnosis 7
- Treating symptoms without establishing a definitive diagnosis for persistent ulcers 7
- Failing to recognize that many cases of recurrent aphthous ulceration are associated with correctable nutritional deficiencies 4, 5
- Not considering biopsy for ulcers persisting beyond 2 weeks 8, 7