J Allergy Clin Immunol Pract. 2022 Apr 9:S2213-2198(22)00342-7. doi: 10.1016/j.jaip.2022.03.030. Online ahead of print.
ABSTRACT
BACKGROUND: An optimal strategy for choosing safe alternative low osmolar contrast media (LOCM) has not yet been established in patients with a history of LOCM-induced anaphylaxis.
OBJECTIVES: To validate the practical pathway in patients with anaphylaxis to LOCMs and to compare two different doses of challenge testing with skin test-negative LOCM.
METHODS: A retrospective cohort study was performed in patients with LOCM-induced anaphylaxis. Patients were challenged with intravenous LOCMs showing negativity in the skin test according to two different protocols: low-dose and high-dose (maximum dose 10 and 30 mL, respectively). Challenge-negative LOCMs were selected for use during computed tomography (CT) scans, and patients received intravenous pretreatment with 4 mg chlorpheniramine and 40 mg methylprednisolone.
RESULTS: Of the 110 challenge tests, there were four (3.6%) positive challenges. Among 106 enhanced CT scans performed using challenge-negative LOCMs, breakthrough reactions (BTRs) occurred in eight (7.6%). BTR rates were not statistically different between the two protocols (8.9% and 6.0% in the low-dose and high-dose challenge, respectively). Compared to the low-dose protocol, the number needed to test of the high-dose challenge test decreased 2.5-fold. Moreover, none of the patients in the high-dose challenge group incurred severe reactions during CT scans with challenge-negative LOCM, while 80% of reactions were severe in the low-dose challenge group.
CONCLUSION: We validated a pathway consisting of a battery of skin testing to LOCMs and challenge with skin test-negative LOCM in patients with LOCM-induced anaphylaxis.
PMID:35413472 | DOI:10.1016/j.jaip.2022.03.030
