Nonfatal systemic reactions to subcutaneous immunotherapy: a 10-year experience

Area of Science:

• Allergy and Immunology
• Clinical Medicine
• Pharmacology

Background:

• Subcutaneous immunotherapy (SIT) is a common treatment for allergic respiratory diseases.
• Assessing the safety profile of SIT is crucial for clinical practice.
• Previous studies have indicated a low risk of adverse events with SIT.

Purpose of the Study:

• To evaluate the incidence and clinical characteristics of nonfatal systemic reactions associated with SIT.
• To identify potential risk factors for systemic reactions during SIT.
• To assess the overall safety of SIT in a large patient cohort over a decade.

Main Methods:

• Retrospective analysis of clinical data from 2,206 outpatients treated with SIT between 1981 and 1991.
• Inclusion of 192,505 administered injections.
• Documentation and categorization of all observed systemic reactions and their timing.

Main Results:

• A total of 115 systemic reactions were recorded, affecting 5.2% of patients (0.06% of injections), with no fatalities.
• The most common reactions were asthma with urticaria (67%) and asthma alone (22%).
• Reactions were most frequent during the maintenance phase, typically occurring within 30 minutes post-injection and managed with routine therapy.

Conclusions:

• SIT is a safe treatment option for respiratory allergies when administered following established clinical guidelines.
• Asthmatic patients showed a higher frequency of reactions, but a significant proportion of affected individuals had no prior asthma history.
• Adherence to good clinical practice is paramount for minimizing adverse events during SIT.