The effect of reducing levels of cat allergen (Fel d 1) on clinical symptoms in patients with cat allergy

Abstract

Treatment of cat allergy normally entails removal of the cat from the household, but cat owners are often unwilling to part with their pets, despite clinically relevant allergies. To determine whether levels of Fel d 1 can be reduced without removal of the cat and whether this will affect symptoms of cat allergy. Cat-allergic patients underwent randomization to either a group instructed in environmental control (EC) and a group with unchanged environment (UE). Dust samples were obtained and settled Fel d 1 measured by enzyme-linked immunosorbent assay. Patients recorded daily nasal inspiratory flow rates. At baseline, 3 months, and 8 months, patients underwent symptom evaluation. Eighteen patients were randomized to the EC group and 22 to the UE group; the final number completing the study was 31, 15 in the EC group, and 16 in the UE group. At 8 months, home Fel d 1 levels had diminished to 6.8% of baseline levels in the EC group, whereas no reduction in levels was noted in the UE group. In the EC group, significant improvements were found in nasal inspiratory flow rate and symptoms compared with the UE group. Patients did not have difficulties adhering to EC measures. A decrease in the allergen load was found in the EC group, which had a significant effect on symptoms of nasal allergy.