Differential Diagnosis for a 14-Month-Old Child with a Painful Lesion on the Tongue

• Single Most Likely Diagnosis
  • Traumatic ulcer (e.g., bite injury): This is a common occurrence in toddlers who are learning to navigate their surroundings and may accidentally bite their tongue, leading to a painful lesion.
• Other Likely Diagnoses
  • Herpes simplex virus (HSV) infection: Oral HSV can cause painful vesicles or ulcers on the tongue and elsewhere in the mouth, especially in young children.
  • Hand, Foot, and Mouth Disease (HFMD): Although more commonly associated with vesicles on the hands and feet, HFMD can also cause oral lesions, including on the tongue.
  • Aphthous ulcers: These are common in children and can appear as painful lesions on the tongue, though they are more typically found on the inside of the cheeks or lips.
• Do Not Miss Diagnoses
  • Erythema multiforme: A skin condition that can also affect the mucous membranes, including the tongue, and is characterized by target-like lesions. It can be a sign of an underlying infection or drug reaction.
  • Stevens-Johnson Syndrome (SJS): A severe form of skin and mucous membrane disorder, usually a reaction to medication or infection. It can cause painful lesions in the mouth, including on the tongue, and is a medical emergency.
• Rare Diagnoses
  • Autoimmune disorders (e.g., pemphigus): These conditions can cause blistering lesions on the skin and mucous membranes, including the tongue, though they are rare in young children.
  • Leukemia or lymphoma: Although extremely rare, these conditions can cause oral lesions, including on the tongue, as part of their presentation.
  • Histoplasmosis or other fungal infections: In immunocompromised children, fungal infections can cause oral lesions, including on the tongue, though this would be uncommon in an otherwise healthy 14-month-old child.