Differential Diagnosis for a Kid with Swollen Tonsils, Low Grade Fever, and Fussiness

• Single Most Likely Diagnosis
  • Viral Pharyngitis: This is the most common cause of swollen tonsils and low-grade fever in children, often accompanied by fussiness due to discomfort. Viruses such as adenovirus, influenza, and respiratory syncytial virus (RSV) are common culprits.
• Other Likely Diagnoses
  • Streptococcal Pharyngitis (Strep Throat): Although less common than viral causes, strep throat is a significant concern due to its potential for complications like rheumatic fever. Symptoms can include swollen, painful tonsils, fever, and fussiness.
  • Tonsillitis: Inflammation of the tonsils can be caused by both viral and bacterial infections, leading to symptoms of swollen tonsils, fever, and irritability.
  • Mononucleosis (Mono): Caused by the Epstein-Barr virus, mono can present with swollen tonsils, fever, and general malaise, although it's more common in adolescents and young adults.
• Do Not Miss Diagnoses
  • Epiglottitis: A potentially life-threatening condition that requires immediate medical attention. It involves inflammation of the epiglottis, which can cause severe respiratory distress, and its symptoms can sometimes be mistaken for a severe sore throat or swollen tonsils.
  • Retropharyngeal Abscess: A serious infection in the tissues at the back of the throat, which can cause severe throat pain, difficulty swallowing, and in severe cases, respiratory obstruction.
  • Peritonsillar Abscess: A collection of pus behind the tonsils that can cause severe throat pain, fever, and difficulty swallowing. It's a complication of tonsillitis and requires prompt medical attention.
• Rare Diagnoses
  • Lemierre's Syndrome: A rare condition characterized by a bacterial infection of the tonsils followed by the spread of the infection to the jugular vein, leading to thrombophlebitis and potentially life-threatening complications.
  • Kawasaki Disease: An acute febrile illness of childhood that can present with fever, irritability, and sometimes swollen lymph nodes, although it's more commonly associated with symptoms like rash, conjunctivitis, and changes to the lips and oral cavity.
  • Diphtheria: A bacterial infection affecting the membranes of the throat and nose, though rare in areas with high vaccination coverage. It can cause a severe sore throat, fever, and a distinctive greyish membrane covering the tonsils and throat.