DHF

Dengue hemorrhagic fever (DHF) is a severe form of dengue virus infection characterized by fever, vascular fragility, and hemorrhagic manifestations that can progress to dengue shock syndrome if not treated. It typically occurs after a person has been infected with a different dengue virus serotype than a previous infection, due to immune enhancement that increases disease severity. Transmission occurs through bites of Aedes mosquitoes, especially Aedes aegypti and Aedes albopictus, which are common in tropical and subtropical regions.

Signs and symptoms usually begin with high fever, headache, retro-orbital pain, and muscle or joint pains. As illness progresses, patients may develop abdominal pain, persistent vomiting, mucosal bleeding, petechiae, and ecchymosis. In DHF, plasma leakage can lead to pleural effusion, ascites, and hemoconcentration, with shock possibly developing in severe cases if leakage is extensive or untreated.

Diagnosis relies on clinical presentation in the appropriate epidemiologic setting, supported by laboratory tests. Early in illness, RT-PCR or NS1 antigen detection can confirm dengue infection; later, dengue-specific IgM and IgG antibodies aid diagnosis. Key laboratory findings include thrombocytopenia and leukopenia, with hemoconcentration indicating plasma leakage.

Management is supportive and time-sensitive, focusing on careful fluid management to restore intravascular volume while monitoring for signs of shock or fluid overload. Severe DHF requires hospitalization and often intensive care. NSAIDs are generally avoided due to bleeding risk, and corticosteroids are not routinely recommended.

Prevention centers on mosquito control and personal protection to reduce transmission. Vaccination with Dengvaxia (CYD-TDV) is approved in some countries for individuals with prior dengue infection (seropositive), typically aged 9–45, and is not advised for seronegative individuals due to safety concerns. Ongoing research seeks safer, more effective vaccines and broader vector-control strategies.