Uncovering new tools for severe antibiotic allergy
Published Online: May 2021
Delayed drug allergies are a group of presumed immunological-mediated adverse drug reactions (IM-ADR) that vary from isolated mild skin conditions to severe cutaneous adverse reactions (SCAR) that are associated with significant disease and mortality. Diagnostic modalities such as skin testing have limited availability in the clinical setting and have variable sensitivity. Other laboratory-based blood assays such as the specialized enzyme-linked immunoSpot (ELISpot) allow to stimulate the patient’s blood with various suspected drugs and have the advantage of avoiding drug re-exposure.
Copaescu and colleagues in The Journal of Allergy and Clinical Immunology: In Practice examined the use of these diagnostic modalities in 81 patients with antibiotic associated delayed IM-ADR from a prospective cohort of 1,346 recruited from two Australian centers.
The authors completed standard allergy investigations such as skin testing with the implicated drugs for 68 (84%) patients and 63 (78%) had an ELISpot assay performed. This laboratory-based tool contributed to the culprit drug diagnosis by identifying 15 (19%) additional cases what were missed with skin testing alone. When looking at the association of these tools, 51 (63%) patients tested were positive to at least one implicated antibiotic. This percentage increased depending on the underlying drug reaction and the causal drug.
The investigators present one of the largest cohorts of antibiotic-associated severe delayed IM-ADR and demonstrate the utility of ELISpot to supplement traditional skin testing approaches. They propose that ELISpot can potentially be performed in specialized immunology laboratories when drug re-exposure is either unsafe or not available. Large collaborative international networks are required to develop and standardize diagnostic approaches such as skin testing combined with laboratory methods and other tools such as genetic testing to improve medication safety after severe delayed IM-ADRs.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.