Improving drug allergy label accuracy by supervised safety- and protocol-driven evaluation.
10.47102/annals-acadmedsg.2022118
- Author:
Chiara Jiamin CHONG
1
;
Karen Jui Lin CHOO
;
Kheng Yong ONG
;
Vivian TAN
;
Janet Beng Neo KHOO
;
Kavitha Garuna MURTHEE
;
Ibrahim Muhammad HANIF
;
Chaw Su NAING
;
Haur Yueh LEE
Author Information
1. Department of Internal Medicine, Singapore General Hospital, Singapore.
- Publication Type:Journal Article
- MeSH:
Humans;
Male;
Middle Aged;
Female;
Prospective Studies;
Drug Hypersensitivity/epidemiology*;
Exanthema;
Urticaria;
Monobactams
- From:Annals of the Academy of Medicine, Singapore
2022;51(11):677-685
- CountrySingapore
- Language:English
-
Abstract:
INTRODUCTION:Drug allergies are often self-reported but of unknown accuracy. We carried out a prospective study to examine the utility and safety of formal allergology evaluation, and to identify factors associated with accurate drug allergy labels.
METHOD:All patients who underwent drug allergy evaluation in our clinic during the study period were recruited. Baseline demographics, characteristics of index hypersensitivity reaction and outcomes of evaluation were recorded.
RESULTS:A total of 331 patients from March 2019 to June 2021 completed drug allergy evaluation to index drugs of concern. There were 123 (37%) male patients, and the mean age was 49 years (standard deviation 17). There were 170 beta-lactam antibiotics, 53 peri-operative drugs, 43 others, 38 non steroidal anti-inflammatory drugs, and 27 non-beta-lactam antibiotic evaluations. Index reaction occurred within 5 years in 165 (50%) patients, with latency of less than 4 hours in 125 (38%) patients. The most common index reactions were rash, angioedema and urticaria. There were 57 (17%) evaluations stratified as low risk, 222 (67%) moderate risk, and 52 (16%) high risk based on multidisciplinary consensus. Allergy label was found to be false (negative drug evaluation) in 248 (75%) patients, while 16/237 (7%) skin tests, 44/331 (13%) in-clinic graded challenge, and 23/134 (17%) home prolonged challenges were positive (true drug allergy). The most common evaluation reactions were rash and urticaria. No cases of anaphylaxis were elicited.
CONCLUSION:Seventy-five percent of drug allergy labels are inaccurate. Risk-stratified, protocolised allergy evaluation is safe. Prolonged drug challenge increases the sensitivity of drug allergy evaluation and should therefore be performed when indicated.
