Dengue fever is a mosquito born arboviral disease caused by four serotypes of dengue virus (DEN-1 to DEN-4). Although the classical type of dengue fever has been endemic in India for many years, the more severe form of disease, dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS), were first reported from Calcutta in 1963. Since then many outbreaks of DHF/DSS have been reported from various parts of the country. Delhi has witnessed two major outbreaks of dengue haemorrhagic fever in the last two decades. It has been noticed that clinical features