Drug hypersensitivity reactions: Response patterns,drug involved,and temporal variations in a large series of patients

Background: drug hypersensitivity reactions (dhrs) are among the most frequent reasons for consultation in allergy departments,and are becoming more common due to increasing prevalence and case complexity. objective: to study the clinical characteristics,drugs involved,diagnostic methods,and temporal variation of dhrs in a large series of patients over a 6-year period. methods: we included all patients attending our department between 2005 and 2010. the diagnosis was performed by in vivo and/or in vitro tests (basophil activation test and specifi c immunoglobulin [ig] e in serum and drug provocation testing [dpt]) when indicated. results: we evaluated 4460 patients who reported 4994 episodes (mean [sd] of 1.13 [0.36] [range,1-3] episodes per patient). based on clinical history,37% of the episodes were attributed to nonsteroidal anti-infl ammatory drugs (nsaids),29.4% to ß-lactam antibiotics (bls),15% to non-bls,and 18.4% to other drugs. analysis of the 1683 patients (37.45%) fi nally confi rmed as allergic showed the most frequent diagnosis to be hypersensitivity to multiple nsaids (47.29%),followed by immediate reactions to bls (18.12%). there was an increase in reactions to non-bls (from 21.2% to 31.9%; p<.03) over the study period,mainly due to an increase in allergy to quinolones (from 0.5% to 6.8%; p<.02); 44% of patients were diagnosed by clinical history,14.6% by skin tests,10.4% by in vitro tests,and 30.8% by dpt. conclusions: nsaids were the drugs most frequently involved in dhrs and the most common diagnosis was urticaria/angioedema with cross intolerance. reactions to emerging drugs such as quinolone derivatives and radiocontrast media are becoming more common.