Résumé
Drug hypersensitivity reactions (DHRs) are the adverse effects of drugs, taken at a dose which is tolerated by normal subjects, which clinically resemble allergy. There are few true epidemiological data on DHRs. The available information requires a cautious interpretation because the pathogenic mechanism has not been demonstrated by diagnostic tests. Both under- and over-diagnosis must be taken into account. DHRs may represent up to one third of adverse drug reactions, be life-threatening, require or prolong hospitalization, and entail changes in drug prescription. They concern more than 7% of the general population, and therefore are an important public health problem. A few risk factors have been pinpointed. Future progress in genetics, as well as well-designed epidemiological studies on hypersensitivity drug reactions, will be helpful in identifying patients at risk of developing such reactions, in particular severe ones, and in implementing early preventive measures. This review describes current data on the incidence, prevalence, mortality, and risk factors of these reactions.