What conditions can cause aphthous ulcers (canker sores)?

From the Guidelines

Canker sores can be caused by a variety of conditions, including traumatic, infectious, allergic factors, and may be associated with skin disease, autoimmune disease, tumor, inflammatory bowel disease, and other underlying health conditions, as noted in a recent expert consensus guideline for diagnosis 1.

Conditions Associated with Canker Sores

Some of the conditions that can cause canker sores include:

• Stress
• Minor injuries to the mouth, such as from dental work, aggressive brushing, or accidental cheek bites
• Food sensitivities, particularly to chocolate, coffee, strawberries, eggs, nuts, cheese, and spicy or acidic foods
• Vitamin deficiencies, especially B-12, zinc, folate, and iron
• Hormonal changes during menstruation
• Certain medications, including NSAIDs like ibuprofen
• Toothpastes containing sodium lauryl sulfate
• Underlying health conditions, such as celiac disease, inflammatory bowel diseases, Behçet's disease, and compromised immune systems
• Genetics, as canker sores often run in families
• Inflammatory bowel diseases, such as Crohn's disease, as seen in a 13-year-old boy with recurrent oral ulcers who was later diagnosed with Crohn's disease 1
• Nasal-type extranodal NK/T-cell lymphoma, a rare type of cancer that can cause oral ulcers, as seen in a 25-year-old woman with a 2-month history of oral ulcers 1

Importance of Diagnosis

It is essential to consult a healthcare provider to rule out underlying conditions, especially if canker sores are frequent or severe. A detailed medical history inquiry, histopathological examination, and screening for ulceration-related systemic diseases can help establish an accurate diagnosis and guide treatment. Early diagnosis and treatment can improve outcomes and reduce the risk of complications, as emphasized in the expert consensus guideline for diagnosis 1.

From the Research

Conditions that can cause canker sores

• Food allergies 2, 3
• Vitamin and microelement deficiencies, such as:
  • Vitamin B12 deficiency 4
  • Folate deficiency 4
• Hormonal disorders 2, 3
• Gastrointestinal disorders, including:
  • Celiac disease 2
  • Crohn's disease 2
  • Ulcerative colitis 2
• Viral and bacterial infections 2, 3
• Mechanical injuries 2, 3
• Stress 2, 3
• Genetic factors, including:
  • Family history 5
  • Specific gene polymorphisms, especially those encoding proinflammatory cytokines 5
• Systemic disorders, such as:
  • Behçet's disease 3
  • Complex aphthosis variants, including ulcus vulvae acutum, MAGIC syndrome, FAPA syndrome, and cyclic neutropenia 3
  • Human immunodeficiency virus (HIV) disease 3
  • Hematinic deficiencies 3