Abstract
BACKGROUND: Sickle cell disease (SCD) is a genetically inherited hemoglobinopathy characterized by chronic hemolysis, vaso-occlusive episodes, and end-organ complications. Individuals with SCD are more vulnerable to infections, and co-infections such as dengue fever can lead to severe clinical manifestations. Late diagnosis of SCD in adulthood is rare but possible, particularly in individuals with a milder phenotype or elevated fetal hemoglobin (HbF). CASE PRESENTATION: We present the case of a 28-year-old male with no known chronic illnesses who was admitted with fever, abdominal pain, and myalgia. Initial investigations revealed thrombocytopenia and elevated liver enzymes, and he tested positive for dengue NS1 antigen. Imaging studies demonstrated splenomegaly, near-complete splenic infarction, distal splenic vein thrombosis, and acute acalculous cholecystitis. Hematological workup revealed anemia and hemolysis, prompting further evaluation. Hemoglobin electrophoresis confirmed previously undiagnosed sickle cell disease (HbS 79%, HbF 16.9%, no HbA). The patient's symptoms improved with supportive care, antimicrobial therapy, and anticoagulation. He remained well at follow-up with resolution of acute findings. CONCLUSION: This case highlights a rare scenario in which dengue fever unmasked a previously unrecognized diagnosis of sickle cell disease (SCD) in adulthood. It underscores the importance of maintaining a high index of suspicion for SCD in adult patients presenting with unexplained thrombotic complications during dengue infection. In dengue-endemic regions, clinicians should be particularly vigilant when faced with atypical presentations such as splenic infarction. The complex interplay between viral infection, hemolytic anemia, and thrombotic risk in SCD further reinforces the need for a comprehensive and multidisciplinary diagnostic approach. CLINICAL TRIAL: Not applicable.