The patient was a previously healthy 23-year-old woman who made an outpatient visit to our hospital's Department of General Internal Medicine after developing pain and edema of the lower legs a week earlier. The patient was diagnosed with eosinophilic cellulitis (EC) based on an increased eosinophil count of 5,418/mm3 and the results of a skin biopsy of the lower leg that showed eosinophilic infiltration of the dermal tissue. Her condition improved after oral prednisone therapy. EC presents clinically as edema and eosinophilia. Therefore, in many cases, patients make an outpatient visit to the internal medicine department. In the present study, the clinical course of nine patients diagnosed with EC as outpatients at our Department of General Internal Medicine over the past 10 years was examined.