Differential Diagnosis for Sore on the Lip
- Single most likely diagnosis
- Cold sore (Herpes Simplex Virus): This is the most common cause of sores on the lip, characterized by a painful, fluid-filled blister that crusts over time. The high prevalence and typical presentation make it the leading diagnosis.
- Other Likely diagnoses
- Canker sore (Aphthous ulcer): These are small, shallow lesions that develop on the soft tissues in the mouth or at the base of the gums. They can be painful but are not contagious.
- Angular cheilitis: This condition is characterized by inflammation of the corners of the mouth, often due to fungal or bacterial infections, and can cause soreness and cracking.
- Lip biting or trauma: Accidental biting of the lip or other forms of trauma can cause sores.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Oral cancer: Although less common, sores on the lip can be a sign of oral cancer, especially if they do not heal. Early detection is crucial for effective treatment.
- Syphilis: The primary stage of syphilis can manifest as a single, painless sore (chancre) on the lip or elsewhere on the body.
- Leukoplakia: This condition, characterized by white patches on the mucous membranes, can sometimes appear as a sore and is associated with an increased risk of oral cancer.
- Rare diagnoses
- Erythema multiforme: A skin condition characterized by target lesions, which can appear on the lips and are often triggered by infections or medications.
- Autoimmune disorders (e.g., pemphigus, lupus): These conditions can cause a variety of skin and mucous membrane lesions, including sores on the lip.
- Behçet's disease: A rare disorder that causes blood vessel inflammation throughout the body and can lead to mouth sores, among other symptoms.