ABSTRACT Secondary haemophagocytic lymphohistiocytosis (SHFLH) is a rare, potentially fatal disorder, most commonly caused by the Epstein–Barr virus. It is characterized by neoplastic proliferation of cells that belong to the monocyte–macrophage system and by varied clinical expression. A girl aged 3 years and 7 months was hospitalized due to continuing high febricity, yellow skin colouring, hepatosplenomegaly and cytopenia in a complete blood count (CBC). Four weeks before hospitalization, she had a lacunar angina and lymphadenopathy. A low number of erythrocytes, leukocytes and thrombocytes were noted in CBC, with anaemia and the presence of virocytes in a peripheral blood smear. Biochemical blood analyses indicated hyperbilirubinaemia, increased values of transaminases, lactic dehydrogenase, ferritin, triglycerides, D-dimer, acceleration of the activated partial thromboplastin time and decreased values of fibrinogen, with increased values of C-reactive protein and procalcitonin. Using an ultrasound examination of the abdomen, hepatosplenomegaly was perceived; using echocardiographic examination, pericardium layering was noticed; and using a roentgen graphic picture of the lungs, the presence of pleural effusion was detected. In a bone marrow biopsy, the percentage of blasts did not exceed 25%, and rare chemophagocytes were noticed. Using serologic tests, positivity to Epstein-Barr virus in IgM class was demonstrated. According to the criteria by Histiocyte Society, there were sufficient criteria to establish a diagnosis of SHFLH. With the exception of symptomatic therapies, according to the protocol for SHFLH treatment, a double antibiotic therapy and IV immunoglobulins were given, to which the patient responded with a clinical and laboratory recovery. Therefore, there was no demand for a treatment protocol with cytostatics or bone marrow transplantation. To resolve a differential diagnosis dilemma in solving cases of uncertain febrile neutropenia.