What are the causes of an oral ulcer (mouth ulcer)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 27, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Oral ulcers should be diagnosed and treated based on a comprehensive assessment of clinical medical history, histopathological examination, and screening for ulceration-related systemic diseases, as recommended by the expert consensus guideline for diagnosis 1. When managing oral ulcers, it is essential to consider the diverse and complex etiologies, including traumatic, infectious, allergic factors, and associations with skin disease, autoimmune disease, tumor, inflammatory bowel disease, and others 1.

Key Considerations

  • The diagnosis of oral ulcers can be challenging due to the lack of typical clinical features in some cases, and a thorough medical history and comprehensive assessments are necessary 1.
  • Recurrent aphthous ulcers (RAU) may be caused by disturbed immune response, genetic predisposition, nutrient deficiency, oral trauma, anxiety, or stress, but the exact cause is often unknown 1.
  • Maintaining good oral hygiene through gentle brushing and flossing, avoiding spicy, acidic, or rough foods, and using antimicrobial mouthwashes containing chlorhexidine 0.12% twice daily can help prevent secondary infection and promote healing 1.

Treatment Approach

  • Topical medications like benzocaine gel (Orajel) or lidocaine rinses applied 3-4 times daily can help reduce pain 1.
  • Pain relief can be managed with acetaminophen 500-1000mg every 6 hours or ibuprofen 400-600mg every 6-8 hours as needed 1.
  • If an ulcer persists beyond two weeks, is unusually large (>1cm), extremely painful, or recurs frequently, medical attention should be sought to rule out underlying conditions like vitamin deficiency, autoimmune disorder, or oral cancer 1.

Prevention

  • Stress reduction, adequate hydration, and a balanced diet rich in vitamins B12, folate, and iron may help prevent recurrence of oral ulcers 1.

From the Research

Causes of Oral Ulcers

  • Recurrent oral ulceration can be caused by numerous factors, including underlying systemic disease 2
  • In children, recurrent aphthous stomatitis (RAS) is the most common underlying diagnosis for oral ulcers 2
  • Other causes of oral ulcers include local and systemic conditions such as erosive lichen planus, benign mucous membrane pemphigoid (BMMP), erythema multiforme, Behçet's disease, allergic stomatitis, and infection 3
  • Some oral ulcers may indicate an underlying systemic condition such as a gastrointestinal dysfunction, malignancy, immunologic abnormality, or cutaneous disease 4

Management and Treatment of Oral Ulcers

  • Management of oral ulcers may include topical agents for symptomatic relief, topical corticosteroids, and systemic agents in severe cases 2
  • Topical antimicrobial and antifungal agents, topical and systemic corticosteroids, topical and systemic analgesics, and systemic immunosuppressive and anxiolytic drugs may be used to manage oral ulcers 3
  • Treatment of chronic recurrent oral aphthous ulcers is symptomatic, mainly with topically applied agents, and is tailored to the severity of the problem in the individual case 5
  • Acyclovir may be used as prophylaxis against oral ulcers in patients with acute myeloid leukaemia receiving remission induction chemotherapy 6

Prevention of Oral Ulcers

  • Hard, acidic, and salty foods and toothpastes containing sodium lauryl sulfate should be avoided to prevent oral ulcers 5
  • Alcohol and carbonated drinks should also be avoided to prevent oral ulcers 5

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.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.