Differential Diagnosis for 9yo Male with Oral Ulcer and Anterior Cervical Lymphadenopathy, Strep Negative

• Single Most Likely Diagnosis
  • Hand, Foot, and Mouth Disease (HFMD): This is a common viral illness in children, characterized by oral ulcers and lymphadenopathy. The absence of a positive strep test and the presence of oral ulcers make HFMD a likely diagnosis.
• Other Likely Diagnoses
  • Herpangina: Another viral illness that causes oral ulcers and can be accompanied by lymphadenopathy. It's similar to HFMD but typically has fewer or no skin lesions on the hands and feet.
  • Aphthous Ulcers: While these are common in children, the presence of significant lymphadenopathy might suggest a more systemic cause. However, if the ulcers are typical of aphthous ulcers and the lymphadenopathy is mild, this could still be considered.
  • Infectious Mononucleosis (Mono): Caused by Epstein-Barr virus (EBV), mono can present with oral ulcers, lymphadenopathy, and fever. A strep test is often negative in mono, but the presence of oral ulcers and significant lymphadenopathy, especially in the absence of other symptoms like sore throat, makes this less likely but still possible.
• Do Not Miss Diagnoses
  • Acute Lymphoblastic Leukemia (ALL): Although rare, ALL can present with lymphadenopathy and oral ulcers due to bone marrow suppression leading to infections. It's crucial to consider this diagnosis due to its severity and the need for prompt treatment.
  • Lymphoma: Similar to ALL, lymphoma can cause lymphadenopathy and, less commonly, oral ulcers. It's a critical diagnosis not to miss due to its implications for treatment and prognosis.
  • Tuberculosis (TB): TB can cause lymphadenopathy and oral ulcers, especially in endemic areas or in individuals with exposure history. It's less common but critical to diagnose due to its public health implications and the need for specific treatment.
• Rare Diagnoses
  • Autoimmune Disorders (e.g., Systemic Lupus Erythematosus, Sjögren's Syndrome): These can cause oral ulcers and lymphadenopathy but are rare in children and would typically be accompanied by other systemic symptoms.
  • HIV Infection: Can cause oral ulcers and lymphadenopathy due to immunosuppression. It's rare in children without known risk factors but should be considered in the appropriate clinical context.
  • Other Viral Infections (e.g., CMV, HSV): These can cause similar symptoms but are less common or would present with additional distinguishing features.