Differential Diagnosis for Mouth Sores

The differential diagnosis for mouth sores can be extensive, given the variety of potential causes. Here's an organized approach to considering the possible diagnoses:

• Single Most Likely Diagnosis

  • Aphthous ulcers (canker sores): These are the most common cause of mouth sores and can be triggered by stress, minor mouth injury, or certain foods. They are typically self-limiting and resolve within a couple of weeks.

• Other Likely Diagnoses

  • Herpes simplex virus (HSV) infection: HSV can cause painful vesicles or ulcers in the mouth, often accompanied by systemic symptoms like fever and malaise during the initial outbreak.
  • Hand, foot, and mouth disease (caused by Coxsackievirus): Characterized by small, painful blisters on the tongue, roof of the mouth, and inside the cheeks, along with a rash on the hands and feet.
  • Oral lichen planus: An autoimmune condition that can cause white, lacy patches; red, inflamed tissues; or open sores in the mouth.
  • Denture-related stomatitis: Inflammation of the tissue under a denture, often due to poor denture hygiene or ill-fitting dentures.

• Do Not Miss Diagnoses

  • Oral cancer: Although less common, mouth sores that do not heal within two weeks can be a sign of oral cancer. Risk factors include tobacco use, alcohol consumption, and human papillomavirus (HPV) infection.
  • Syphilis: The primary stage of syphilis can manifest as a single, painless chancre in the mouth, which, if untreated, can progress to more severe stages.
  • Tuberculosis (TB): Oral TB can cause ulcers, patches, or other lesions in the mouth, and is particularly concerning in immunocompromised individuals or those with exposure history.
  • Leukemia: Certain types of leukemia can cause mouth sores or ulcers due to bone marrow suppression leading to immunodeficiency.

• Rare Diagnoses

  • Behçet's disease: A rare disorder that causes blood vessel inflammation throughout the body, leading to symptoms including mouth sores, genital sores, skin rashes, and eye inflammation.
  • Pemphigus vulgaris: An autoimmune disease that causes severe blistering of the skin and mucous membranes, including the mouth.
  • Erythema multiforme: A skin condition characterized by target lesions, which can also affect the mucous membranes, including the mouth, and can be triggered by infections or medications.
  • Autoimmune disorders like lupus or rheumatoid arthritis: These conditions can sometimes manifest with oral ulcers among their myriad symptoms.

Each of these diagnoses has distinct features and risk factors, and a thorough medical history, physical examination, and sometimes additional testing are necessary to determine the cause of mouth sores in a given individual.