Investigação clínico laboratorial de pacientes com suspeita de reações de hipersensibilidade alérgica a fármacos em hospital terciário

Abstract

Allergic drug reactions account for 6.5% of hospital admissions, prolonged hospitalization 15.1% of patients and are severe in 6.7% of patients. There are difficulties in understanding the immune mechanisms, diagnosis and treatment of patients. Therefore, such reactions are considered a Public Health problem. The objective of this study was to describe the cases of patients with suspected allergic hypersensitivity to drugs and to evaluate the response of individuals to skin tests. A total of 63 patients were included in the study. The experimental design was a cross-sectional observational study from June 2008 to October 2011. We applied a questionnaire to investigate the clinical and laboratory informations. Eight patients received other diagnosis and three died due to other reasons, so that 52 patients completed the study. Most patients were men (56.36%), non atopic, with a median age of 52 year. The drugs most commonly implicated were NSAIDs and the oral administration was the most commonly route used. It was documented 69 suspected reactions; most of them were considered as delayed hipersensitivity. Maculopapular rash and erythema multiforme were the most frequent manifestations. According to the severity of the reactions, most was considered moderate (72.46%). The patch test was performed in 22 patients for investigation of delayed reaction. Seven cases were positive (31.81%), DRESS (rash with eosinophilia and systemic symptoms) caused by captopril (+), contact eczema by rifamycin (+ +), lichenoid eruption by captopril (+), maculopapular rash + ampicillin and cephalexin to angioedema (+), two cases of fotoeczema one by captopril and another by AAS, both with positive results (+) and one case of Stevens-Johnson syndrome caused by phenytoin (++). For immediate hypersensitivity, 3 in 10 patients have shown positive results for prick test with AAS diluted to 1/1000. It was possible to confirm the liability of the drug reactions in 19 (27.53%), which demonstrated the importance of application of skin tests in the clinical investigation of allergic drug reactions. As for causality, 26 reactions were considered possible, 20 defined, 13 probable, 9 and a conditional reaction was considered not related to drugs. Given its importance, the performance of skin tests with these patients has opened perspectives on the possibility to incorporate this service in routine outpatient Dermatology HUWC.