What is the most likely diagnosis for a 6-year-old boy with high fevers, sore throat, and a rash that developed after the fever?

In this scenario, the combination of high fevers, sore throat, and rash developing after the fever is highly suggestive of a viral infection. Of the options provided, the clinical presentation aligns with infectious mononucleosis rather than sweat fever.

Infectious mononucleosis, commonly caused by the Epstein-Barr virus, often presents in children and adolescents with symptoms such as high fever, severe sore throat (due to pharyngitis), lymphadenopathy, and fatigue. A rash can occur in some cases, particularly if the child has been treated with certain antibiotics like ampicillin or amoxicillin.

Erythema infectiosum typically presents with a "slapped cheek" rash in children, often preceding respiratory symptoms and would not usually present in the same way as described. Measles also includes a distinct prodrome of fever, cough, and conjunctivitis, followed by a characteristic rash; however, it typically follows a more specific pattern and features. Sweat fever is not a well-defined medical condition in pediatrics and doesn’t correlate with the symptoms presented.

Thus, the most likely diagnosis, given the symptoms described, would be infectious mononucleosis, making it critical to recognize the patterns of presentation and common viral