Abstract
<jats:p>Perinatally acquired Human Immunodeficiency Virus (HIV) infection is associated with several haematological abnormalities, most commonly anemia. Polycythemia is not a well known adverse effect of these drugs, particularly with integrase strand transfer inhibitor (INSTI)-based antiretroviral therapy (ART). We report a 12-year-old male with perinatally acquired HIV infection developing persistent polycythemia after initiation of a Dolutegravir (DTG)-based regimen. Hemoglobin levels steadily increased to 18.3 g/dL. Exclusion of both primary and secondary causes of erythrocytosis, including JAK2 mutation analysis, serum erythropoietin levels, bone marrow examination, hypoxia, and cardiac disease, was unremarkable. The patient required multiple therapeutic phlebotomies and low-dose aspirin for thrombosis prophylaxis. ART modification was limited by intolerance to alternative regimens, necessitating continuation of DTG therapy. This case highlights a rare but clinically significant adverse effect of DTG-based ART and emphasises the importance of regular hematological monitoring in patients receiving INSTI-containing regimens.</jats:p>