Differential Diagnosis for Oral Lesion
- Single most likely diagnosis
- Herpes Simplex Virus (HSV) infection: The initial description of a yellow circular canker sore and the subsequent appearance of a C-shaped white sore could be indicative of an HSV infection, which often presents with vesicular lesions that can rupture and form a crust, appearing white.
- Other Likely diagnoses
- Aphthous Ulcer (Canker Sore): The initial yellow circular lesion could be an aphthous ulcer, which is a common, benign condition. The C-shaped white sore might represent a healing stage or a secondary infection.
- Traumatic Ulcer: If the patient slept in an unusual position or had an object in their mouth, a traumatic ulcer could have formed, potentially appearing as a white sore after waking.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Oral Cancer: Although less likely, any new or changing oral lesion warrants consideration of oral cancer, especially if the patient has risk factors such as tobacco use or a history of radiation therapy.
- Necrotizing Ulcerative Gingivitis (Trench Mouth): This condition can present with painful ulcers and could potentially be life-threatening if not treated promptly due to the risk of sepsis.
- Rare diagnoses
- Erythema Multiforme: A rare skin condition that can affect the mucous membranes, including the mouth, and might present with target-like lesions or ulcers.
- Behçet's Disease: A form of vasculitis that can cause oral ulcers, among other symptoms, though it is relatively rare and would typically be accompanied by other systemic symptoms.