Effect of pet removal on pet allergic asthma

Allergen avoidance has been recommended in the management of allergic asthma. Very few studies have assessed the effect of pet removal on pet allergic asthma.

We examined the effect of pet removal from homes on pulmonary function testing, airway hyperresponsiveness, and medication use.

Prospective, nonrandomized, nonblinded observational study.

Subjects included 20 symptomatic patients with newly diagnosed pet allergic asthma who were keeping domestic animals, including hamsters, cats, dogs, and ferrets, and were sensitized to the animals. They were treated with inhaled corticosteroids or other medications according to recommendations by level of severity of the Global Initiative for Asthma. Methacholine inhalation tests were performed regularly before and after starting medication. Clinical features were compared between the patients who gave away their pets according to recommendations by the clinician (removal group) and the patients who refused to give away their pets (keeping group).

There were 10 patients in both the removal group and the keeping group. After >or= 1 year of follow-up with or without pet removal, a 5.9-fold increase in the provocative concentration of methacholine causing a 20% fall in FEV(1) was observed in the removal group compared with a 2.3-fold increase in the keeping group (p = 0.04). There were no significant differences in the changes in FEV(1) and peak flow variability. Finally, no patient received inhaled corticosteroids in the removal group, whereas all but one of the patients needed beclomethasone dipropionate (mean dose, 600 mug/d) in the keeping group.

This study indicates that removal of pets from homes reduces airway responsiveness in patients with pet allergic asthma more than optimal pharmacotherapy alone, thereby enabling a decrease in inhaled corticosteroid doses.