The most common first symptoms were seizure or coma following fever in our cases. From our experience, we have found that common febrile convulsion is often the most difficult disease in the differential diagnosis of HSES in the early stage. Concerning febrile convulsions: prolonged seizures lasting 5 to 10 minutes are relatively common, the laboratory data including CSF is near normal, CT scans reveal normal or slightly edematous conditions, and elevation of CK levels and WBC counts are often seen in cases with prolonged seizures [9] [10] [11] [12] . Even though followup CT scans could provide useful information about cerebral edema [13] [14] [15] , our results showed that the initial CT finding was not useful in making the HSES diagnosis. When an abnormality on the CT was discovered, the patient's condition was critical.