Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 20 1 2026 02 09 30 37 EN Rahaf Alhasan Department of Pediatrics, King Abdullah University Hospital, Irbid, Jordan Hebah Alraiqib Department of Pediatrics, King Abdullah University Hospital, Irbid, Jordan Basheer Alghizzawi Faculty of Medicine, King Abdullah University Hospital, Irbid, Jordan Abdelrahman Al-Sweedan Faculty of Medicine, King Abdullah University Hospital, Irbid, Jordan Suleimman Al-Sweedan Department of Pediatric Hematology/Oncology, King Abdullah University Hospital, Irbid, Jordan 2024 12 05 2026 01 04 caused by uncontrolled activation of macrophages and cytotoxic T cells. It is frequently underdiagnosed, leading to significant morbidity and mortality in pediatric populations. Early identification and treatment are critical to improving prognosis. Materials and Methods: This retrospective study analyzed demographic, clinical, and laboratory data of pediatric patients aged 0 to 18 years diagnosed with HLH according to the HLH-2004 criteria. Patients admitted to our center between February 2021 and February 2023 were included. We aimed to describe common presenting symptoms, laboratory  abnormalities , treatment modalities, and patient outcomes. Results: A total of 35 children diagnosed with HLH were included; 51% were female. The mean age was 6.1 years, with an age range from birth to 18 years. Fever was the most frequent presenting symptom, reported in 85% of cases. Hemophagocytosis in bone marrow aspirates was detected in 41% of patients. The overall mortality rate was 11%. Notably, 20% of patients tested positive for anti-COVID-19 IgG antibodies, suggesting a possible temporal association with the development of HLH, Comparative analysis indicated that deceased patients had significantly lower fibrinogen levels (p = 0.04) and higher triglyceride levels (p = 0.03). Treatment regimens varied according to clinical presentation and severity. Conclusion: HLH remains a challenging diagnosis due to its variable presentation and potential to rapidly progress to life-threatening immune activation. Prompt recognition and timely initiation of appropriate therapy are vital for improving outcomes in affected children. Increased awareness among clinicians and early intervention can reduce morbidity and mortality associated with this condition. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/2351 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/2351/1117