Table 1.

1997 World Health Organization (WHO) case definition for dengue hemorrhagic fever and dengue shock syndrome^*

DHF, the following must all be present:
Fever, or history of acute fever, lasting 2–7 days, occasionally biphasic
Hemorrhagic tendencies, evidenced by at least one of the following:
A positive tourniquet test
Petechiae, ecchymoses, or purpura
Bleeding from the mucosa, gastrointestinal tract, injection sites, or other locations
Hematemesis or melaena
Thrombocytopenia (100,000 cells/mm3 or less)
Evidence of plasma leakage caused by increased vascular permeability, manifested by at least one of the following:
A rise in the hematocrit equal to or > 20% above average for age, sex, and population
A drop in the hematocrit following volume replacement treatment equal to or > 20% of baseline
Signs of plasma leakage such as pleural effusion, ascites, and hypoproteinemia
Case definition for dengue shock syndrome:
All of the above four criteria for DHF must be present, plus evidence of circulatory failure manifested by:
Rapid and weak pulse, and
Narrow pulse pressure (< 20 mm Hg)
or manifested by:
Hypotension for age, and
Cold, clammy skin and restlessness.

^*HF = dengue hemorrhagic fever.