Hemophagocytic lymphohistiocytosis secondary to Varicella Zoster in paediatric Acute Lymphoblastic Leukemia

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening syndrome of excessive immune activation. HLH can be inherited or secondary to other diseases. An association between primary varicella-zoster virus infection and HLH has already been reported in adults. Extreme hyperferritinemia is seen in HLH in the pediatric population. Rapid progression and significant mortality require a high clinical index of suspicion and prompt diagnosis for optimal outcome. We report 3 children with acute lymphoblastic leukemia in remission who presented with varicella infection-induced HLH. Initially, laboratory data showed neutropenia in two patients and, hepatitis in one patient. Antiviral therapy, and antibiotics along with supportive treatment were initiated. Patients had persistent symptoms with raised serum ferritin, high clinical index of suspicion for HLH was kept. Treatment was directed towards suppressing the overt immune response. Prednisolone was started and tapered over eight weeks. All three patients responded well to treatment and were discharged.