RESUMEN
A 49-year-old man was admitted to the hospital with complaints of fatigue, epistaxis and a skin rash. The whole blood count revealed isolated thrombocytopenia (4,000/mL), and the patient was admitted to the hematology department with a diagnosis of immune thrombocytopenia. He did not respond to steroid treatment for 15 days, and a subfebrile fever developed during this period. A diagnosis of acute brucellosis was considered due to positive serological tests and a blood culture positive for Brucella spp. After starting doxycycline and rifampicin therapy, the patient's thrombocyte count increased to 15,000/mL on the third day, to 41,000/mL on the sixth day and was normal on the 21st day of treatment. A diagnosis of brucellosis must be considered in patients presenting with severe and isolated thrombocytopenia in countries where brucellosis is endemic.