Differential Diagnosis for Labial Pain

• Single most likely diagnosis
  • Cold sore (Herpes Simplex Virus): This is often the most common cause of labial pain, characterized by the appearance of vesicles or ulcers on the lip, typically preceded by a prodrome of tingling or burning.
• Other Likely diagnoses
  • Angular cheilitis: Inflammation of the corners of the mouth, which can cause pain and discomfort, often due to fungal or bacterial infections.
  • Dry lip (cheilitis): Pain and discomfort due to dryness, which can be caused by environmental factors, licking the lips, or certain medications.
  • Mucocele: A mucous cyst that can form on the lip, usually as a result of trauma to the minor salivary glands, causing pain and swelling.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Squamous cell carcinoma: Although rare, it's crucial to consider this diagnosis, especially in older adults or those with a history of sun exposure, as it can present with persistent labial pain or ulcers.
  • Erythema multiforme: A skin condition that can cause painful ulcers on the lips and elsewhere, sometimes triggered by infections or medications, which can be severe and requires prompt treatment.
• Rare diagnoses
  • Primary syphilis: Can cause a painless chancre on the lip, but in some cases, it may be painful, making it a rare but important consideration in the differential diagnosis of labial pain.
  • Autoimmune disorders (e.g., pemphigus, lupus): These conditions can cause oral and labial lesions and pain, though they are less common causes of isolated labial pain.