Subcutaneous Immunotherapy With High-Dose Cat and Dog Extracts: A Real-life Study

Background: Data on the efficacy of immunotherapy administered to patients with cat or dog allergy are scarce. Objective: We aimed to evaluate the safety and efficacy of subcutaneous immunotherapy (SCIT) in patients with allergy to cat and dog dander.

Consecutive patients with rhinitis and/or asthma related to sensitization to cat or dog dander were included in a pragmatic, real-life, prospective, observational study. All patients had specific IgE to cat, dog, or both. SCIT was administered using an infusion pump over 3 sessions as part of a rush protocol, followed by monthly administration over 12 months. We recorded adverse events, clinical outcomes, pulmonary function, FeNO, symptoms of rhinitis and asthma, quality of life (QoL), Asthma Control Test (ACT) score, and visual analog scale (VAS) score at baseline, 6 months, and 12 months.

The study population comprised 66 patients (38 females, 46 allergic to cat and 20 to dog), with ages ranging from 9 to 59 years. During the up-dosing phase, in which the infusion pump was used, 8.1% of doses elicited a systemic reaction and 5.4% caused a local reaction, while 9.3% of doses administered during the maintenance phase (ie, without an infusion pump) induced a systemic reaction. No local reactions were recorded. A significant improvement in FEV1, symptoms of rhinitis and asthma, QoL, use of medication, VAS score, and ACT score was observed at 6 months and continued at 12 months. Clinical improvement with cat extract was significantly better than with dog extract.

High-dose SCIT has substantial clinical value in many cat- and dog-allergic patients.