Aphthous Ulcers
BASICS
DESCRIPTION
- Painful circumscribed lesions of the mouth, typically located on the nonkeratinized surfaces (i.e., tongue or buccal mucosa)
- Greek word aphtha coined by Hippocrates refers to sores of mucosal surfaces.
- Colloquially called “canker sores”
EPIDEMIOLOGY
- More common in developed countries
- Slightly more common in males compared to females
- Frequently occur in childhood and adolescence but can occur at any point in the lifespan
- Subtypes: minor (a.k.a. Mikulicz aphthae; 70–85% of cases), major (10–15%), and herpetiform (1–10%)
- Minor and major typically present with 1 to 5 lesions.
- Lesions of major subtype are larger ($1 cm in diameter) and heal more slowly than smaller lesions of minor subtype.
- Herpetiform may present with 10 to 100 lesions.
RISK FACTORS
- Local trauma
- Physiologic or emotional stress
- Personal or family history of autoimmune disease
- Nutrition
- Vitamins D, C, and B12 deficiencies
- Folate, zinc, iron, selenium, and copper deficiencies are also supported by some literature.
- Diet rich in spicy and/or acidic foods
- Toothpastes containing sodium lauryl sulfate
- Alcohol use
- Poor sleep quality
- Medications
- Angiotensin-converting enzyme (ACE) inhibitors
- β-Blockers
- Calcineurin and mTOR inhibitors
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Bisphosphonates
- Endocrine changes (e.g., menstrual cycles)
- Heavy tobacco smoking (one pack of cigarettes per day for $5 years) may be protective.
Genetics
A large genome-wide association study found 97 variants altering the odds of developing mouth ulcers, many in genes related to T-cell immunity, and imposing a Th1-type (proinflammatory) immune response.
GENERAL PREVENTION
- Avoid toothpaste with sodium lauryl sulfate.
- Consume softer, less spicy foods.
- Vitamin B12 supplementation
ETIOLOGY
- May be primary or secondary to chronic infection, autoimmune diseases, or immunodeficiencies
- Aphthae can predate the development of systemic autoimmune disease.
PATHOPHYSIOLOGY
- Pathophysiology incompletely understood, but oral dysbiosis is theorized to play some role.
- Immune activation occurs in response to oral keratinocyte antigens. This may involve upregulation of HLA class II within the mouth.
- Biopsy specimens show markedly elevated IL-2, suggesting the important role played by T lymphocytes.
- Other cytokines such as tumor necrosis factor (TNF) are also upregulated.
- Altered enzymatic composition of saliva, although this may be compensatory
COMMONLY ASSOCIATED CONDITIONS
- Trauma, especially from dentures, implants, or dental instrumentation
- Infection
- HIV
- Tuberculosis
- Coxsackie virus
- Epstein-Barr virus
- Herpes simplex virus (HSV)
- Gastrointestinal
- Crohn disease
- Celiac disease
- Autoimmune/autoinflammatory
- Antineutrophilic cytoplasmic antibody (ANCA)-associated vasculitis
- Behçet disease
- Mouth and genital ulcers with inflamed cartilage (MAGIC) syndrome
- Familial Mediterranean fever (rarely)
- Periodic fever with aphthous stomatitis, pharyngitis, and adenitis (PFAPA)
- Reactive arthritis
- Sweet syndrome
- Relapsing polychondritis
- Immunodeficiency
- Cyclic neutropenia
- Hyper-IgD syndrome
- Food allergy
- Drug induced (e.g., methotrexate)
- Oropharyngeal malignancy (rare; suspect if persistent and no response to therapy)
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Citation
Cabana, Michael D., editor. "Aphthous Ulcers." 5-Minute Pediatric Consult, 9th ed., Wolters Kluwer, 2025. Pediatrics Central, peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/619011/all/Aphthous_Ulcers.
Aphthous Ulcers. In: Cabana MDM, ed. 5-Minute Pediatric Consult. Wolters Kluwer; 2025. https://peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/619011/all/Aphthous_Ulcers. Accessed June 10, 2026.
Aphthous Ulcers. (2025). In Cabana, M. D. (Ed.), 5-Minute Pediatric Consult (9th ed.). Wolters Kluwer. https://peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/619011/all/Aphthous_Ulcers
Aphthous Ulcers [Internet]. In: Cabana MDM, editors. 5-Minute Pediatric Consult. Wolters Kluwer; 2025. [cited 2026 June 10]. Available from: https://peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/619011/all/Aphthous_Ulcers.
* Article titles in AMA citation format should be in sentence-case
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T1 - Aphthous Ulcers
ID - 619011
ED - Cabana,Michael D,
BT - 5-Minute Pediatric Consult
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PB - Wolters Kluwer
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5-Minute Pediatric Consult

