What is the best initial testing approach for recurrent oral ulcers?

Diagnostic Algorithm for Recurrent Oral Ulcers

For recurrent oral ulcers, the best initial testing approach includes thorough clinical history and examination, followed by blood tests (complete blood count, glucose, HIV, syphilis serology) if ulcers persist beyond 2 weeks or don't respond to initial treatment. 1, 2

Initial Evaluation

• Begin with detailed clinical history and oral examination to identify common causes like trauma, infection, or recurrent aphthous stomatitis 1, 2
• Document duration, frequency, number, size, shape, and location of ulcers 2
• Assess for typical morphological features - recurrent aphthous ulcers present as well-demarcated, oval/round ulcers with white/yellow pseudomembrane and erythematous halo 1
• Evaluate for local factors (sharp teeth edges, appliances) that may cause traumatic ulceration 1, 2

Testing Algorithm for Persistent Ulcers

First-line Testing (for ulcers >2 weeks or non-responsive to treatment)

• Full blood count - to screen for anemia, leukemia, and other blood disorders 1
• Fasting blood glucose - hyperglycemia can predispose to fungal infections 1
• HIV antibody testing - to rule out HIV-associated ulceration 1
• Syphilis serology - to exclude syphilitic ulcers 1

Second-line Testing (based on clinical suspicion)

• Nutritional deficiency screening - iron, folate, vitamin B12 levels 1, 2
• Autoimmune markers - for suspected autoimmune conditions 2
• Specific antibody tests (Dsg1, Dsg3, BP180, BP230) - if bullous diseases are suspected 1

Biopsy Considerations

• Biopsy is indicated when ulcers persist >2 weeks despite treatment 1
• Multiple biopsies may be needed if ulcers have different morphological characteristics 1
• For suspected bullous diseases, direct immunofluorescence (DIF) should be performed 1, 2

Special Considerations

• For recurrent aphthous stomatitis with typical presentation and no systemic symptoms, extensive testing may not be initially required 1, 3
• If anemia or leukemia is suspected based on blood count, additional testing including bone marrow biopsy may be necessary 1
• For ulcers associated with systemic symptoms (fever, weight loss, joint pain), broader evaluation for systemic diseases is warranted 2

Common Pitfalls to Avoid

• Relying solely on clinical appearance without appropriate testing for persistent ulcers 2
• Inadequate biopsy technique (too small or superficial) may miss important diagnostic features 2
• Overlooking systemic causes of recurrent oral ulcers can lead to delayed diagnosis 2, 3
• Treating symptoms without establishing definitive diagnosis for persistent ulcers 2

Specialist Referral

• Refer to oral medicine specialist if ulcers persist >2 weeks or don't respond to initial treatment 2
• Specialists can coordinate multidisciplinary care when needed (gastroenterology for IBD-related ulcers, hematology for blood disorders) 2