Differential Diagnosis of Painful Ulcerative Oral Lesions

Primary Differential Diagnoses

The American Academy of Oral Medicine recommends that any oral lesion persisting beyond 2 weeks, especially without response to 1-2 weeks of symptomatic treatment, requires biopsy 4
NK/T-cell lymphoma (nasal-type extranodal) presents with serious erosion and necrosis covered by yellowish-white pseudomembrane, confirmed through HE staining and immunohistochemical studies 1, 2
Oral tuberculosis manifests as widespread ulcers and masses on the palate, requiring identification of granulomatous inflammation with Langhans-type giant cells and acid-fast bacilli on Ziehl-Nielsen staining 1, 2
Acute leukemia can present with widespread necrotic ulcers covered by smooth, thick yellowish-white pseudomembrane, particularly when neutrophil counts are severely decreased 2

Before proceeding to biopsy, obtain full blood count to exclude anemia, leukemia, and neutropenia 2
Blood coagulation studies should be performed to rule out surgical contraindications 2
Fasting blood glucose should be checked to identify diabetes (a susceptibility factor for invasive fungal infection) 2
HIV antibody and syphilis serology should be tested to exclude infectious causes 4

Multiple biopsies should be performed when ulcers involve multiple sites with different morphological characteristics 2
Excisional biopsy is preferred for small lesions (≤3mm) to allow full histopathologic assessment 4
Incisional biopsy from the ulcer edge (including adjacent normal tissue) is appropriate for larger lesions 1, 2

For confirmed oral tuberculosis, four-drug anti-tuberculous therapy is required, including isoniazid, rifampicin, pyrazinamide, and ethambutol 1, 2
For Stevens-Johnson syndrome/TEN, intensive supportive oral care is essential, including white soft paraffin ointment to lips, mucoprotectant mouthwash, and benzydamine hydrochloride oral rinse or spray 5
For systemic disease-associated ulcers, treatment of the underlying condition is paramount, such as caspofungin infusion for invasive fungal infection 2

Never assume a small or benign-appearing lesion is non-malignant—squamous cell carcinoma can present as small white ulcerative lesions 4
Do not delay biopsy beyond 2 weeks for any persistent ulcer, as this represents excessive delay in diagnosing potentially life-threatening conditions 3, 4
Avoid missing synchronous lesions by failing to perform complete oral cavity inspection including all mucosal surfaces, floor of mouth, and oropharynx 4
Do not overlook systemic disease associations—always inquire about gastrointestinal symptoms, constitutional symptoms, and immunosuppression 1, 2, 3