Differential Diagnosis for a 12-year-old Boy

Given the information that the 12-year-old boy is negative for strep, flu, and Covid, we can consider the following differential diagnoses:

• Single Most Likely Diagnosis
  • Viral pharyngitis: This is a common condition in children, often presenting with sore throat, fever, and other non-specific symptoms. The negative tests for strep, flu, and Covid make viral pharyngitis a plausible diagnosis due to its high prevalence and the broad range of viruses that can cause it.
• Other Likely Diagnoses
  • Allergic rhinitis: Seasonal or perennial allergies could cause symptoms such as a sore throat, cough, and runny nose, especially if the boy is exposed to allergens.
  • Sinusitis: Given the age and the absence of specific viral infections, sinusitis (either viral or bacterial) could be a consideration, especially if there are symptoms like facial pain, nasal congestion, or cough.
  • Mononucleosis (Mono): Although less common, mono caused by Epstein-Barr virus (EBV) can present with sore throat, fever, and fatigue, and is more common in adolescents.
• Do Not Miss Diagnoses
  • Epiglottitis: A potentially life-threatening condition that requires immediate attention. Although rare, it can present with severe sore throat, difficulty swallowing, and shortness of breath.
  • Peritonsillar abscess: A complication of tonsillitis that can cause severe throat pain, difficulty swallowing, and fever. It requires prompt medical attention.
  • Lemierre's syndrome: A rare but serious condition following a throat infection, characterized by fever, sore throat, and neck pain, which can lead to sepsis and other complications.
• Rare Diagnoses
  • Kawasaki disease: An acute febrile illness of childhood that can present with sore throat, fever, rash, and other symptoms. It's rare but important to consider due to potential cardiac complications.
  • Tuberculosis (TB): Although uncommon in many areas, TB can cause chronic symptoms including cough, fever, and weight loss. It's essential to consider in children with exposure risks or persistent symptoms.
  • Histoplasmosis or other fungal infections: In endemic areas, these infections can mimic common viral or bacterial illnesses but require specific treatment.

Each of these diagnoses should be considered in the context of the patient's full clinical presentation, including physical examination findings, exposure history, and additional diagnostic tests as necessary.