What is the cause of an oral mucosal lesion (mouth sore) on the inside of the mouth?

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Differential Diagnosis for Sore on Inside of Mouth

  • Single Most Likely Diagnosis
    • Aphthous ulcers (canker sores): These are the most common cause of sores inside the mouth, often presenting as small, painful, and shallow ulcers on the mucous membranes. They can be triggered by stress, minor mouth injury, or certain foods.
  • Other Likely Diagnoses
    • Oral herpes (HSV-1): This viral infection can cause painful sores or blisters on the inside of the mouth, lips, or around the oral area. It's highly contagious and can be triggered by stress, sunlight, or illness.
    • Traumatic ulcers: Accidental bites, dental work, or sharp edges of teeth or dental appliances can cause sores inside the mouth.
    • Denture-related irritation: Poorly fitting dentures can cause friction and lead to sores on the mucous membranes.
    • Oral lichen planus: A chronic inflammatory condition that can cause white patches, redness, and sores inside the mouth.
  • Do Not Miss Diagnoses
    • Oral cancer: Although less common, sores inside the mouth can be a sign of oral cancer, especially if they persist, grow, or are accompanied by other symptoms like difficulty swallowing or a lump in the neck.
    • Tuberculosis (TB): In rare cases, TB can manifest as oral ulcers, especially in immunocompromised individuals.
    • Syphilis: The secondary stage of syphilis can cause mucous patches or ulcers in the mouth.
  • Rare Diagnoses
    • Erythema multiforme: A rare skin condition that can cause ulcers and lesions in the mouth, often triggered by infections or medications.
    • Pemphigus vulgaris: A rare autoimmune disease that can cause blisters and sores in the mouth and on the skin.
    • Behçet's disease: A rare condition that can cause recurrent oral ulcers, along with other symptoms like genital ulcers and eye inflammation.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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