Classification and epidemiology of hypersensitivity drug reactions.

Nonimmune hypersensitivity reactions are unpredictable adverse drug reactions that are clinically similar to allergic reactions for which no drug-specific antibodies or T lymphocytes are identified. Few tools allow a definite diagnosis, and most of the available ones need to be validated. True epidemiologic data are limited, and most of the available information on the incidence, mortality, and socioeconomic impact should be discussed with caution.