What is the etiology of recurrent oral ulcers (mouth sores)?

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Last updated: February 28, 2025View editorial policy

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From the Guidelines

Recurrent oral ulcers are often caused by a combination of local and systemic factors, including trauma, stress, nutritional deficiencies, hormonal changes, and underlying medical conditions such as inflammatory bowel disease, autoimmune disorders, and infections like tuberculosis and HIV. The evaluation of recurrent oral ulcers should begin with a thorough history and physical examination to identify potential causes. First, distinguish between aphthous stomatitis (canker sores) and other conditions by noting the appearance, location, and pattern of ulcers. Common etiologies include trauma, stress, nutritional deficiencies (particularly B12, folate, iron, and zinc), hormonal changes, food allergies, and certain medications. Systemic conditions that may present with oral ulcers include Behçet's disease, inflammatory bowel disease, celiac disease, HIV, and autoimmune disorders like lupus 1.

Some key points to consider in the diagnosis of recurrent oral ulcers include:

  • Laboratory testing should include complete blood count, iron studies, vitamin B12, folate levels, and celiac screening
  • For persistent or severe cases, consider referral to oral medicine or dermatology for biopsy to rule out malignancy or specific conditions like lichen planus
  • Patients should be advised to avoid spicy foods, acidic beverages, and potential allergens while maintaining good oral hygiene
  • Treatment typically begins with topical corticosteroids like triamcinolone dental paste 0.1% applied 2-4 times daily, or dexamethasone elixir as a rinse
  • For pain management, topical lidocaine 2% can provide temporary relief
  • Systemic therapy with prednisone (40-60mg daily with taper) may be necessary for severe cases
  • Identifying and addressing the underlying cause is crucial for preventing recurrence and improving quality of life, as seen in cases of Crohn’s disease 1 and oral tuberculosis 1.

In cases where the diagnosis is unclear, a biopsy may be necessary to rule out underlying conditions, and further testing such as blood work and imaging studies may be needed to determine the underlying cause of the oral ulcers 1.

From the Research

Etiology of Recurrent Oral Ulcers

The etiology of recurrent oral ulcers is complex and multifactorial. Some of the common causes include:

  • Infection 2, 3, 4
  • Immune-related factors 2, 3, 4, 5
  • Trauma 2, 3, 4, 6
  • Neoplastic factors 2
  • Medications 3, 5
  • Autoimmune diseases 3, 4, 5
  • Systemic diseases 3, 4, 5
  • Genetic predisposition 5, 6
  • Nutritional deficiencies 5
  • Food allergies 5
  • Stress 5, 6
  • Smoking 6
  • Viral and bacterial infections 6

Classification of Recurrent Oral Ulcers

Recurrent oral ulcers can be classified into different types, including:

  • Traumatic ulceration 3
  • Chemical ulceration 3
  • Recurrent aphthous stomatitis 3, 5
  • Medication-related ulceration 3
  • Infectious ulceration 3, 4
  • Mucocutaneous disease 3, 4
  • Autoimmune/systemic disease 3, 4, 5

Diagnosis of Recurrent Oral Ulcers

Diagnosis of recurrent oral ulcers involves a detailed patient history, clinical examination, and laboratory tests. Some of the clinical criteria used to identify the cause of oral ulcers include:

  • Vesicles or bullae 4
  • Constitutional signs and symptoms 4
  • Lesions on the skin and/or other mucosa 4
  • Biopsy and culture may be indicated in some cases 2, 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Diagnosis of oral ulcers.

The Mount Sinai journal of medicine, New York, 1998

Research

Treatment strategies for recurrent oral aphthous ulcers.

American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists, 2001

Research

Recurrent oral ulcers--an overview.

Compendium of continuing education in dentistry. (Jamesburg, N.J. : 1995). Supplement, 2001

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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