Differential Diagnosis for 3 y/o Female with Fever, Cough, Phlegm, and Generalized Rash

• Single Most Likely Diagnosis
  • Viral Exanthem (e.g., Roseola): This is a common condition in children characterized by a high fever followed by a rash. The timing of the rash appearing after the fever, especially worsening at night, could fit this diagnosis, although the cough and phlegm might suggest a concurrent or preceding respiratory infection.
• Other Likely Diagnoses
  • Respiratory Infections with Secondary Rash (e.g., Pneumonia with a viral exanthem): The initial symptoms of fever, cough, and phlegm suggest a respiratory infection. A secondary rash could be part of the illness or a reaction to an antibiotic if one was prescribed.
  • Allergic Reactions or Atopic Dermatitis: If the rash worsens at night, it could be related to allergies or atopic dermatitis, especially if there's a history of atopy or if the child has been exposed to new allergens.
• Do Not Miss Diagnoses
  • Bacterial Infections (e.g., Scarlet Fever, Pneumococcal Disease): These conditions can present with fever, cough, and a rash. Scarlet fever, for example, is characterized by a sandpapery rash that appears after the onset of fever and can be accompanied by a cough if there's a concurrent respiratory infection.
  • Meningitis or Sepsis: Although less likely given the description, these conditions can present with fever and rash (e.g., petechial rash in meningococcemia) and are medical emergencies.
• Rare Diagnoses
  • Kawasaki Disease: This condition is characterized by fever, rash, conjunctivitis, and changes to the lips and oral cavity. It's a rare but important diagnosis to consider due to its potential to cause cardiac complications.
  • Juvenile Idiopathic Arthritis (JIA): Systemic JIA can present with fever, rash, and systemic symptoms, although it's less common in this age group and the presence of a cough and phlegm might not be the primary symptoms.