TOPLINE:

An analysis of surveillance data from approximately 84.1 million subcutaneous immunotherapy (SCIT) visits involving about 4.9 million patients revealed that practices that reduced vial concentrations when restarting therapy after treatment gaps showed a reduced risk for severe systemic reactions.

METHODOLOGY:

• Researchers sought to assess the incidence of fatal and nonfatal systemic reactions and injection-related infections as well as clinicians’ preferred dose adjustments when restarting SCIT after treatment gaps.
• They analyzed data collected through annual surveys of physician members of the American Academy of Allergy, Asthma & Immunology and the American College of Allergy, Asthma and Immunology between 2018 and 2023.
• They categorized nonfatal systemic reactions as grade 1 (mild), grade 2 (moderate), grade 3 (severe), or grade 4 (very severe).

TAKEAWAY:

• Overall, four SCIT-related fatal reactions were observed.
• For patients who were more than 7 weeks late for doses in the maintenance vial, practices that reduced the dose by one vial lower showed a significantly lower risk for grade 4 systemic reactions than those who did not reduce the dose to that extent (P = .02).
• For patients who were more than 28 to less than 35 days late for doses in the buildup vial, practices that decreased the dose to the next lower vial showed lower rates of grade 3 and 4 systemic reactions than those that did not (P = .03).
• For patients who were more than 7 to less than 21 days late for doses in the maintenance vial, practices that increased to the next dose after gaps in maintenance therapy showed a significant increase in grade 3 and 4 systemic reactions compared with those that repeated the previous dose (P < .05).

IN PRACTICE:

“Uncontrolled and/or severe asthma remain the major contributing risk factors for life-threatening anaphylaxis following SCIT injections. This highlights the importance of verifying good asthma control at the time when SCIT is prescribed and prior to each injection, as well as using caution when prescribing SCIT for patients with severe asthma,” the authors of the study wrote.

SOURCE:

Tolly G. Epstein, MD, MS, with the University of Cincinnati College of Medicine, Cincinnati, was the corresponding author of the study, which was published online on October 29, 2025, in The Journal of Allergy and Clinical Immunology: In Practice.

LIMITATIONS:

The rise in the incidence of severe and very severe systemic reactions from 2018 to 2021 may have reflected reporting bias and declining survey responses, possibly due to fewer immunotherapy prescriptions during the COVID pandemic, the retirement of participating allergists, survey fatigue, and a lack of awareness among newer allergists.

DISCLOSURES:

This study was funded by the American Academy of Allergy, Asthma & Immunology and the American College of Allergy, Asthma and Immunology. All authors reported receiving funding from these organizations.

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