Treatment of Recurring Canker Sores (Aphthous Ulcers)
Start with topical corticosteroids as first-line therapy: betamethasone sodium phosphate 0.5 mg dissolved in 10 mL of water used as a rinse-and-spit solution 2-4 times daily, or clobetasol 0.05% ointment mixed in 50% Orabase applied twice daily to localized lesions on dried mucosa. 1, 2
First-Line Topical Treatments
Corticosteroids (Primary Recommendation)
- Betamethasone sodium phosphate 0.5 mg in 10 mL water as rinse-and-spit 2-4 times daily for multiple or widespread ulcers 1, 2
- Clobetasol 0.05% ointment mixed in 50% Orabase applied twice weekly to dried mucosa for localized lesions 1, 2
- Triamcinolone acetonide 0.1% paste applied directly to dried ulcer 2-4 times daily for localized lesions 2
- Fluticasone propionate nasules diluted in 10 mL water twice daily 1
Pain Management
- Topical anesthetics: viscous lidocaine 2% before meals 2, 3
- Benzydamine hydrochloride rinse or spray every 3 hours, particularly before eating 2
- Barrier preparations: Gelclair or Gengigel mouth rinse/gel applied three times daily for mucosal protection and pain control 1, 2
- Benzocaine for temporary pain relief associated with canker sores 4
Important caveat: If using benzocaine, stop and consult a physician if symptoms do not improve in 7 days or if irritation, pain, or redness persists or worsens 4
Second-Line Treatments for Refractory Cases
Topical Immunomodulators
Intralesional Therapy
- Intralesional triamcinolone injections weekly (total dose 28 mg) in conjunction with topical clobetasol gel or ointment (0.05%) for ulcers unresponsive to topical treatment alone 1, 2
Systemic Therapy for Severe Recurrent Cases
When to Escalate
Reserve systemic therapy for patients with highly symptomatic ulcers, frequent recurrences (≥4 times per year), or failure of topical treatments 5, 6, 7
Systemic Options
- Oral corticosteroids: prednisone/prednisolone 30-60 mg or 1 mg/kg for 1 week, followed by dose tapering over the second week 1, 2
- Colchicine: first-line systemic therapy for recurrent aphthous stomatitis, especially if associated with erythema nodosum or genital ulcers 2, 7
- For refractory cases: consider azathioprine, interferon-alpha, TNF-alpha inhibitors, or apremilast 2
- Thalidomide: most effective for severe RAS but reserved as alternative to oral corticosteroids due to toxicity and cost 5, 7
Supportive Care and Prevention
Oral Hygiene
- Clean mouth daily with warm saline mouthwashes 2
- Use antiseptic oral rinses twice daily (1.5% hydrogen peroxide or 0.2% chlorhexidine digluconate) 2
Dietary and Lifestyle Modifications
- Avoid hard, acidic, and salty foods 6
- Avoid toothpastes containing sodium lauryl sulfate 6
- Avoid alcohol and carbonated drinks 6
Concurrent Infections
- Critical pitfall: Treat concurrent candidal infection with nystatin oral suspension or miconazole oral gel before or during corticosteroid therapy 1
Treatment Algorithm by Severity
Mild, localized ulcers: Start with topical anesthetics (lidocaine, benzocaine) and barrier preparations, add topical corticosteroids if insufficient 1, 2, 4
Moderate, multiple ulcers: Begin with betamethasone rinse or fluticasone dilution 2-4 times daily, combine with pain management 1, 2
Severe or refractory ulcers: Add intralesional triamcinolone or escalate to tacrolimus 0.1% ointment 1, 2
Highly symptomatic or frequent recurrences: Initiate systemic corticosteroids or colchicine, consider immunomodulatory agents for persistent cases 1, 2, 7
Common Pitfalls to Avoid
- Do not taper corticosteroids prematurely before disease control is established 2
- Refer to specialist if ulcers last more than 2 weeks or do not respond to 1-2 weeks of treatment 2
- Consider biopsy for ulcers lasting over 2 weeks to rule out malignancy or other conditions 2
- Screen for underlying conditions: Check for nutritional deficiencies (iron, folates), celiac disease, inflammatory bowel disease, HIV, or Behçet's disease in patients with recurrent aphthous stomatitis 6, 7