Clinical Features of Drug Allergy and Factors Affecting Drug-Related Anaphylaxis: Single-center Experience of the Tertiary University Hospital

Background-Aims: Drug hypersensitivity is defined as any unfavorable reaction that occurs after the administration of any drug. We aim to determine the frequency, etiology, and clinical features of drug hypersensitivity reactions (DHRs), and to evaluate the factors affecting drug-related anaphylaxis among the patients admitted to the outpatient allergy clinic of the tertiary university hospital. Materials-methods: In this cross-sectional study, medical records of the 8295 patients who visited the allergy outpatient clinic of Sivas Cumhuriyet University Hospital from 2nd July 2018 to 10th December 2019 were retrospectively reviewed by the hospital data system using the ICD-code Y57.4. The frequency, etiologies, demographic and clinical features of the DHRs were evaluated. Results: Among the 8295 patients who visited the allergy outpatient clinic of Sivas Cumhuriyet University Hospital, 159 patients with a mean age of 40,52± 14,85 years (129 female, 30 male) were evaluated with the diagnosis of DHRs. The frequency of DHRs among admissions was found to be approximately 2%. Accompanying allergic diseases included respiratory (17%), cutaneous (10%), venom (n=3), drug (7%), and food hypersensitivity (n=2). Multiple allergic diseases were detected in 20%. Eighty-six % (n=138) could recognize the culprit drug. The causes of drug allergy were non-steroidal anti-inflammatory drugs (NSAIDs) (27%), beta-lactams (16%), co-sensitization to beta-lactams and NSAIDs (8%), antimicrobials except beta-lactams (8%), and other kinds of drugs (39%). Type 1 reaction occurred in 80%, type 4 in 21%, non-immune mediated in 7, and mixed type composed of type 1 and 4 in 9 patients. Anaphylaxis occurred in 46,5%. Fifteen% had grade 2, 22% had grade 3, and 4 had grade 4 anaphylactic reactions. According to systematical assessment, cutaneous symptoms were observed in 93%, respiratory in 38%, cardiovascular in 29,5%, neurologic in 25%, and gastrointestinal in 11%. Allergy to NSAIDs (88,6 %) and beta-lactams (82,5%) were more frequent in type 1 reactions than in type 4 and mixed type reactions (p