Dengue shock syndrome, usually accompanied by hemorrhagic signs, is much more serious and results from increased vascular permeability leading to shock. In mild DHF/DSS, restlessness, lethargy, thrombocytopenia (<100,000/mL), and hemoconcentration are detected 2-5 days after the onset of typical dengue fever, usually at the time of defervescence. The maculopapular rash that often develops in dengue fever may also appear in DHF/DSS. In more severe cases, frank shock is apparent, with low pulse pressure, cyanosis, hepatomegaly, pleural effusions, ascites, and in some cases severe ecchymoses and gastrointestinal bleeding. The period of shock lasts only 1 or 2 days, and most patients respond promptly to close monitoring, oxygen administration, and infusion of crystalloid or--in severe cases--colloid.Treatment is symptomatic. Aspirin should be avoided due to bleeding risk. Volume replacement and blood transfusions may be indicated in patients with shock. With intensive care suppo, moality rates are 1% or less. Coicosteroids have not been shown to help. No existing antivirals are effective. ref:harrison&;s principles of internal medicine,ed 18,pg no 2217