Not Just Another Rash

A 6-year-old girl with a 5-day history of fever, progressive rash, and arthritis is described. Fever accompanied by a rash is common presenting complaint for children in the emergency department. The differential diagnosis is fairly broad and can be grouped into 5 categories: immune mediated, rheumatologic, oncologic, infectious, and postinfectious. The evaluation of these patients is largely directed by clues provided on history and physical examination, including complete travel history and animal exposures. Further testing commonly includes complete blood count, acute phase reactants, and potentially joint aspiration.