D1.194 - Real-World Effectiveness of Polymerized Dog Allergen Immunotherapy in Allergic Rhinoconjunctivitis and Asthma

Dog is a major source of perennial allergen exposure and a common trigger of allergic rhinoconjunctivitis and asthma. Removing the dog from the household often has a relevant emotional impact. Allergen immunotherapy (AIT) is the only disease-modifying treatment, but real-world data on the effectiveness of polymerized dog extract AIT are scarce.

Retrospective observational study including dog-allergic patients with allergic rhinoconjunctivitis, with or without asthma, treated with dog alergoid AIT (highly purified, glutaraldehyde-modified allergen and depigmented, polymerized extracts) at Infanta Leonor University Hospital, Madrid. Clinical and laboratory data were collected at baseline and after 12 months, including demographic variables, total and specific IgE, type of dog exposure, associated allergic sensitizations, patient-reported clinical progression (Likert scale), disease severity according to the ARIA and GINA classifications and pharmacological treatment.

Twenty-two patients were included (median age 29.9 yo; 64% male). All patients had allergic rhinoconjunctivitis, and 91% asthma. Median total-IgE level was 269.3kU/L (IQR 478.5), and median dog-specific-IgE 14.9kU/L (IQR 31.1). Dog exposure was: daily 81.8%, intermittent 13.6% and occupational 4.5%. Clinical symptoms with other allergens were reported for pollens (50%), cats (40.9%), and molds (4.5%).

At baseline, 63.6% of patients presented with moderate-to-severe rhinitis; at 1-year follow-up, no patients remained in this category. Clinical improvement was observed in 87% (74% mild rhinitis, 26% asymptomatic), with no cases of worsening (p<0.001).

Moderate persistent asthma decreased from 81.8% at baseline to 22.7% after AIT. Overall, 63.6% improved by ≥1 GINA step, with no asthma worsening (p=0.00048).

After 12 months of AIT, patient-reported clinical outcomes and overall symptom burden improved significantly (p<0.001), with a concomitant reduction in antihistamine use (p=0.001), ICS/LABA therapy (p=0.020), and short-acting bronchodilators (p<0.001).

Dog alergoid AIT was associated with significant clinical improvement in allergic rhinoconjunctivitis and asthma, along with a substantial reduction in medication use, supporting its effectiveness in real-world clinical practice.