Differential Diagnosis for Mouth Sores and Oral Thrush in an Immunocompetent 47-year-old Female

• Single Most Likely Diagnosis
  • Recurrent Aphthous Stomatitis (Canker Sores): This is a common condition characterized by the recurrent formation of benign and non-contagious mouth ulcers (canker sores) in otherwise healthy individuals. The cause is not entirely understood, but it is thought to be related to a combination of genetic, immune, and environmental factors.
• Other Likely Diagnoses
  • Oral Lichen Planus: An inflammatory condition that affects the mucous membranes inside the mouth. It can cause white, lacy patches; red, inflamed tissues; or open sores. The exact cause is unknown, but it is believed to be related to an autoimmune response.
  • Herpes Simplex Virus (HSV) Infection: Although more commonly associated with immunocompromised individuals, HSV can cause oral lesions in immunocompetent individuals, particularly during primary infection or reactivation.
  • Denture-Related Stomatitis: This condition is associated with the use of dentures, especially if they are not properly fitted or cleaned. It can lead to inflammation and soreness in the mouth.
• Do Not Miss Diagnoses
  • Squamous Cell Carcinoma: Although rare, oral cancer can present as a persistent mouth sore. Early detection is crucial for effective treatment, making it a diagnosis that should not be missed.
  • Lymphoma: Certain types of lymphoma can initially present with oral lesions. Given the potential severity of lymphoma, it is essential to consider this diagnosis, even if it is less likely.
  • Syphilis: Oral lesions can be a manifestation of secondary syphilis. Given the potential for serious complications if left untreated, syphilis should be considered in the differential diagnosis.
• Rare Diagnoses
  • Erythema Multiforme: A skin condition characterized by target lesions, which can also affect the mucous membranes, including the mouth. It is often triggered by infections or medications.
  • Pemphigus Vulgaris: A rare autoimmune disease that causes blistering of the skin and mucous membranes. Oral lesions are often the first sign of the disease.
  • Behçet's Disease: A form of vasculitis that can cause a wide range of symptoms, including oral ulcers, genital ulcers, and inflammation in parts of the eye. It is rare and more commonly found in certain geographic regions.