Neonatal dengue: A late-onset sepsis mimicker, a clinical description

Dengue is a major arboviral infection in tropical regions, but neonatal involvement remains uncommon and under-recognised. Clinical overlap with late-onset neonatal sepsis often leads to diagnostic delay and unnecessary antimicrobial exposure. We report a term male neonate who presented on day 16 of life with high-grade fever, respiratory distress, lethargy, rash, leucopoenia and severe thrombocytopenia and was initially managed as severe late-onset neonatal sepsis. Persistent fever and worsening thrombocytopenia plummeting to 10,000/μL prompted evaluation for dengue, which revealed non-structural protein-1 (NS1) antigen positivity with negative immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies. Ultrasonography demonstrated features of serositis. The mother developed fever 1 day before the neonate and was also NS1 antigen positive, supporting post-natal mosquito-borne acquisition. Once the diagnosis of dengue was confirmed, antibiotics were discontinued, fluid management was individualised using functional echocardiography and the neonate improved and was discharged after 5 days of hospitalisation. Post-natal dengue should be considered in febrile neonates from endemic regions. Early NS1 testing enables timely diagnosis, appropriate management and avoidance of unnecessary antibiotic use.