Febrile Exanthem with Hyperferritinemia.

Diagnosis of an adult with acute generalized exanthem coupled with spiking fevers, arthralgias, and myalgias requires careful consideration. History and physical examination are basic necessities, while laboratory studies can be valuable adjuncts. The authors present a case of adult onset Still's disease, discuss the differential diagnoses, and highlight the utility of high serum ferritin in identifying this febrile exanthem.