Clinical Outcomes of Cat Allergen Immunotherapy in Patients With Allergic Rhinitis: A Real-World Study

Cat allergy is a common cause of allergic rhinitis and asthma and is associated with significant symptom burden and impaired quality of life. Complete avoidance of cat allergens is often impractical, and allergen-specific immunotherapy (AIT) represents a potential disease-modifying treatment option. However, real-life data regarding the effectiveness and safety of cat allergen immunotherapy remain limited.

To evaluate the real-life clinical effectiveness and safety of subcutaneous cat allergen immunotherapy using a cat allergen extract in patients with cat-induced allergic rhinitis and/or asthma.

This retrospective observational study included patients who received subcutaneous cat allergen immunotherapy for at least 6 months between January 2023 and December 2025. Sensitization to cat allergen was confirmed by both skin prick testing and serum cat-specific IgE (≥0.35 kU/L). Clinical outcomes, including symptom scores, medication scores, Visual Analog Scale (VAS), and Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) scores, were assessed at baseline and during follow-up. Changes between baseline and the sixth month of treatment were analyzed using nonparametric statistical methods.

A total of 12 patients were included, all of whom were female, with a mean age of 35.17 ± 8.68 years. Asthma was present in 25% of patients. At the sixth month of immunotherapy, significant improvements were observed across all evaluated clinical parameters. Median symptom scores decreased from 3.0 to 1.0 (P = 0.002), medication scores from 2.0 to 1.5 (P = 0.038), and VAS scores from 9.0 to 5.0 (P = 0.002). RQLQ scores also showed a significant reduction from 113.0 to 86.0 (P = 0.028). Improvements were associated with large effect sizes. Ten patients achieved a >30% reduction in VAS scores. Moderate correlations were observed between changes in symptom and medication scores and improvements in quality of life. Immunotherapy was generally well tolerated; moderate-to-severe systemic reactions occurred in a subset of patients, with no life-threatening reactions or permanent treatment discontinuation.

In this real-life cohort, subcutaneous cat allergen immunotherapy was associated with significant improvements in clinical symptoms, medication use, and quality of life, with an acceptable safety profile. These findings support the role of cat allergen immunotherapy as an effective treatment option in selected patients with persistent symptoms despite medical therapy.