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TOPLINE:

In children evaluated for a possible macrolide allergy, intradermal testing with a suspected culprit drug at 0.05 mg/mL showed high specificity (92.7%) but limited sensitivity. To confirm an allergy diagnosis, oral provocation testing (OPT) remains necessary, according to researchers.

METHODOLOGY:

• Researchers analyzed data from 102 children (mean age, 72 months) with suspected macrolide allergy who underwent drug allergy testing between 2017 and 2024.
• Children who had had immediate reactions within 1 hour of receiving clarithromycin underwent skin prick tests (SPTs), followed by intradermal tests if SPTs were negative.
• Those who had had delayed reactions (6 hours after drug intake) received patch tests and delayed intradermal readings.
• To confirm the diagnosis, OPTs were subsequently performed for clarithromycin with a maximum daily dose of 15 mg/kg and for azithromycin with a maximum dose of 5 mg/kg.

TAKEAWAY:

• For immediate-type reactions, intradermal testing with clarithromycin 0.05 mg/mL had a sensitivity of 33.3% (95% CI, 0%-66.7%) and a specificity of 92.7% (95% CI, 82.9%-100%); at a higher concentration of 0.5 mg/mL, sensitivity increased to 100%, whereas specificity decreased to 78.9%.
• Nearly 9% of patients had an allergic reaction confirmed.
• In one case, a patient with clarithromycin allergy had a positive result with azithromycin too, yielding a cross ‐ reactivity rate of 11.1%.
• The likelihood of macrolide allergy was higher in patients with a previous drug hypersensitivity reaction (odds ratio [OR], 41; P = .003) or a family history of drug allergy (OR, 5.2; P = .026).

IN PRACTICE:

“The low rate of confirmed macrolide allergy may be due to infection ‐ related rashes being misclassified as drug allergy or the involvement of nonimmunological mechanisms,” the authors of the study wrote. “While OPT is considered diagnostically necessary, its applicability should be evaluated on a case ‐ by ‐ case basis, considering the risk ‐ benefit balance for each patient,” they added.

SOURCE:

Deniz Özçeker, MD, with Prof. Dr. Cemil Taşcıoğlu City Hospital, Istanbul, Türkiye, was the corresponding author of the study, which was published online on August 26 in Clinical and Translational Allergy.

LIMITATIONS:

The single-center design may limit the generalizability of the findings, and the small number of macrolide allergy cases may reduce the study’s statistical power.

DISCLOSURES:

The authors reported having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.