Differential Diagnosis of Red Patch on Tongue

The differential diagnosis for a red patch on the tongue can be categorized into the following groups:

• Single Most Likely Diagnosis

  • Geographic tongue: This is the most common cause of a red patch on the tongue, characterized by a well-demarcated, erythematous area with a depapillated surface, often with a serpentine or geographic pattern. It is a benign condition with no known cause, but it can be associated with stress, nutritional deficiencies, or allergies.

• Other Likely Diagnoses

  • Erythema migrans (migratory stomatitis): This condition presents with multiple, small, red patches that move around the oral cavity, including the tongue. It is often associated with stress, hormonal changes, or nutritional deficiencies.
  • Fissured tongue: While not exclusively a red patch, fissured tongue can present with erythematous areas, especially if there is associated inflammation or trauma to the tongue.
  • Oral lichen planus: This chronic inflammatory condition can cause red, white, or mixed lesions on the tongue, often with a lace-like pattern.

• Do Not Miss Diagnoses

  • Oral cancer: Although less common, a red patch on the tongue can be a sign of oral squamous cell carcinoma, especially if it is persistent, ulcerated, or associated with other symptoms like pain, bleeding, or difficulty swallowing.
  • Infectious diseases: Certain infections like histoplasmosis, tuberculosis, or syphilis can cause oral lesions, including red patches on the tongue, and are critical to diagnose due to their systemic implications.

• Rare Diagnoses

  • Pemphigus vulgaris: An autoimmune disease that can cause blistering lesions in the mouth, including the tongue, which may appear as red patches after the blisters rupture.
  • Erythroplakia: A rare, potentially malignant condition characterized by a red patch on the mucous membrane that cannot be rubbed off and is often associated with an increased risk of cancer.
  • Kawasaki disease: Although primarily affecting children, this condition can cause oral manifestations, including redness of the tongue, along with other systemic symptoms like fever, rash, and lymphadenopathy.