Atypical Dengue Fever Presentation With Severe Leukopenia: A Case Report From an Endemic Border Region.

Dengue virus infection is increasingly recognized in South Texas, particularly in areas bordering Mexico. Although many cases are mild and self-limiting, dengue can present with atypical features, including hematological abnormalities and bleeding, even in the absence of plasma leakage. A 22-year-old Hispanic woman presented to a hospital in South Texas with hematemesis, fever, and gastrointestinal symptoms following travel to northeastern Mexico (Monterrey, Nuevo Leon). Initial laboratory workup revealed severe leukopenia and neutropenia, mild thrombocytopenia, and elevated liver enzymes, but no evidence of plasma leakage. A bone marrow biopsy was performed due to persistent cytopenias, revealing a reactive process consistent with viral infection. The patient improved with supportive care, including hydration, antipyretics, and symptom management, which reflects the mainstay of dengue management. This case illustrates an atypical dengue presentation marked by hematological derangements without classic features, such as hemoconcentration or plasma leakage. It underscores the diagnostic challenge dengue poses in non-typical cases, the importance of maintaining clinical suspicion in endemic areas, and the need for judicious use of invasive investigations and blood product support. Dengue may present atypically with severe cytopenias and bleeding without plasma leakage. Clinicians in endemic areas such as South Texas should consider dengue in febrile patients with cytopenias, even in the absence of plasma leakage, and avoid unnecessary interventions when supportive care suffices.