Dengue hemorrhagic fever occurs when several types of virus are present at the same time or when the patient has contracted a second or third virus after previous infections by another type. Prior immunity to a different Dengue virus type is important in the production of this severe disease. Early symptoms of Dengue hemorrhagic fever are similar to those of Dengue fever but after several days the patient becomes irritable, restless , and sweaty followed by a shock-like state. Bleeding may occur from minor injuries.
Death generally occurs from shock .
If the patient survives, recovery begins after a one-day crisis period. Availability of vaccines varies and may be a problem. Mosquito abatement programs may reduce the risk of infection but vaccination is the only sure method of prevention. If the person appears dehydrated, rehydration with IV fluids is often necessary. A transfusion of fresh blood or platelets corrects bleeding problems, and oxygen therapy may be needed to correct abnormally low blood oxygen.