What are the treatment options for recurring aphthous ulcers (canker sores)?

Treatment of Recurring Canker Sores (Aphthous Ulcers)

For recurring aphthous ulcers, start with topical high-potency corticosteroids as first-line therapy: betamethasone sodium phosphate 0.5 mg dissolved in 10 mL water as a rinse-and-spit solution four times daily, or clobetasol 0.05% ointment mixed with Orabase applied directly to localized ulcers. 1, 2, 3

First-Line Treatment Algorithm

Topical Corticosteroids (Primary Treatment)

• For multiple or difficult-to-reach ulcers: Use betamethasone sodium phosphate 0.5 mg in 10 mL water as a 3-minute rinse-and-spit preparation four times daily 1, 2, 3
• For localized, easily accessible ulcers: Apply clobetasol propionate 0.05% mixed in equal amounts with Orabase directly to dried mucosa twice daily 1, 2, 3
• Alternative option: Fluticasone propionate nasules diluted in 10 mL water twice daily 3

Adjunctive Pain Management

• Benzydamine hydrochloride oral rinse or spray every 3 hours, particularly before eating, for mild to moderate pain 1, 2
• Viscous lidocaine 2% applied up to 3-4 times daily for more severe pain 1, 2, 4
• Gelclair mucoprotectant gel three times daily to form a protective coating over ulcerated surfaces 1, 2, 3

Supportive Oral Hygiene

• Clean mouth daily with warm saline mouthwashes to reduce bacterial colonization 1, 2
• Use antiseptic oral rinses twice daily: either 1.5% hydrogen peroxide mouthwash or 0.2% chlorhexidine digluconate mouthwash (can dilute chlorhexidine by 50% to reduce soreness) 1, 2
• Apply white soft paraffin ointment to affected lips every 2 hours if lips are involved 1, 2

Second-Line Treatment for Refractory Cases

When First-Line Therapy Fails After 7-10 Days

• Tacrolimus 0.1% ointment applied twice daily for 4 weeks for recalcitrant ulcers 2, 3
• Intralesional triamcinolone injections (weekly, total dose 28 mg) in conjunction with topical clobetasol 0.05% 1, 2, 3

Systemic Therapy for Severe or Highly Recurrent Cases

• High-dose pulse corticosteroids: 30-60 mg (or 1 mg/kg) oral prednisone/prednisolone for 1 week, followed by dose tapering over the second week for highly symptomatic or frequently recurrent ulcers 1, 2, 3
• Consider systemic options like colchicine or pentoxifylline in consultation with specialists for refractory cases 5

Treatment of Secondary Infections

Candidal Infection (If Suspected)

• Nystatin oral suspension 100,000 units four times daily for 1 week 1, 2, 3
• Alternative: Miconazole oral gel 5-10 mL held in mouth after food four times daily for 1 week 1, 2, 3

Critical Pitfalls to Avoid

• Do not use topical anesthetics alone without anti-inflammatory therapy, as they only provide temporary pain relief without addressing the underlying inflammatory process 1
• Avoid sodium lauryl sulfate-containing toothpastes, as well as hard, acidic, salty foods, alcohol, and carbonated drinks that can exacerbate ulcers 5
• Do not continue topical therapy beyond 2 weeks without reassessment—if ulcers persist despite appropriate topical corticosteroids, escalate to intralesional or systemic therapy 1, 3
• Screen for underlying systemic conditions (nutritional deficiencies, Behçet's disease, inflammatory bowel disease) in patients with severe or unusually frequent recurrences 5, 6
• Ensure proper diagnosis before treatment—slow healing may indicate secondary HSV infection requiring antiviral therapy rather than continued immunosuppression 1

Evidence Quality Considerations

The recommendations are based primarily on expert opinion from the European Society for Medical Oncology (ESMO) guidelines 1 and the British Journal of Dermatology guidelines 1, as high-quality randomized controlled trials for aphthous ulcer treatment remain limited 7. The Cochrane review found insufficient evidence to definitively support any single systemic intervention, though this likely reflects methodological limitations rather than true lack of efficacy 7. Individual patients often respond to specific treatments, making the stepwise approach outlined above the most pragmatic clinical strategy.