Differential Diagnosis for Apthous Ulcer on the Cheek

• Single most likely diagnosis:
  • Apthous ulcer (canker sore): This is the most likely diagnosis due to the common occurrence of apthous ulcers on the cheeks, lips, and other parts of the mouth. They are typically small, painful, and self-limiting.
• Other Likely diagnoses:
  • Traumatic ulcer: This could be due to accidental biting of the cheek or other forms of oral trauma, leading to ulcer formation.
  • Herpes simplex virus (HSV) infection: Although more commonly associated with the lips (cold sores), HSV can cause ulcers on the cheeks, especially if the individual has a history of HSV infections.
  • Minor salivary gland tumor or mucocele: These are benign growths that can sometimes ulcerate and appear similar to apthous ulcers.
• Do Not Miss diagnoses:
  • Squamous cell carcinoma: Although rare, any oral ulcer that does not heal within a couple of weeks should be evaluated for the possibility of oral cancer, especially in individuals with risk factors such as smoking or tobacco use.
  • Tuberculosis (TB): Oral TB can manifest as ulcers, although this is uncommon. Given the potential severity of TB, it's crucial not to miss this diagnosis, especially in individuals from endemic areas or with compromised immune systems.
  • Syphilis: The primary stage of syphilis can present with a single, painless ulcer (chancre), which could be mistaken for an apthous ulcer. This diagnosis is critical due to the implications for sexual health and the potential for congenital syphilis.
• Rare diagnoses:
  • Behçet's disease: A rare condition characterized by recurrent apthous ulcers, along with genital ulcers and ocular inflammation.
  • Eosinophilic ulcer: A rare, self-limiting condition that can present with ulcers on the oral mucosa, often associated with eosinophilia.
  • Autoimmune disorders (e.g., pemphigus, lupus): These conditions can cause oral ulcers but are less common and typically associated with other systemic symptoms.