Allergic Rhinitis and its Impact on Asthma - ARIA

ALLERGIC RHINITIS AND ITS IMPACT ON ASTHMA GUIDELINES ● 2010 – V. 9/8/2010
II. Treatment of allergic rhinitis
Reducing allergen exposure
Question 7
Should methods aimed at reducing exposure to house dust mites be
used in patients allergic to dust mite allergens?
Summary of findings
Two systematic reviews assessed the efficacy of house dust mite avoidance measures in patients
with perennial allergic rhinitis (110) (see evidence profiles 1 to 3 for question 7) or asthma (111,
112) (see evidence profiles 4 to 6 for question 7).
We found three r<strong>and</strong>omised trials that examined multifaceted interventions to reduce environmental
allergen exposure in children with atopic asthma leaving in inner city, i.e. in densely populated
neighbourhoods in large metropolitan areas inhabited by low income families (113-116).
Benef<strong>its</strong>
No certain benef<strong>its</strong> were found from using single or combined physical or chemical methods aimed
at reducing exposure to house dust mite allergens in patients with persistent allergic rhinitis.
However, the available evidence is of very low quality. In contrast, there is moderate quality
evidence showing that impermeable bedding has no effect on symptoms of rhinitis. Similarly, no
benef<strong>its</strong> were observed in studies using physical <strong>and</strong>/or chemical methods to reduce exposure to
house dust mite allergens in patients with asthma.
Of the three r<strong>and</strong>omised trials that examined multifaceted interventions to reduce environmental
allergen exposure in children with atopic asthma, the Inner-City Asthma Study (113, 114) found
fewer days with symptoms, unscheduled clinic vis<strong>its</strong>, <strong>and</strong> less use of beta-agonist inhalers in the
intervention group, compared to the controls. However, the intervention aimed at reducing the
exposure to many indoor allergens <strong>and</strong> environmental tobacco smoke, most of the children were
sensitive to many indoor allergens, had moderate or severe asthma, <strong>and</strong> less than 50% of them were
receiving appropriate maintenance treatment according to the guidelines. Another r<strong>and</strong>omized
controlled trial (115) of multiple methods to reduce environmental allergen exposure in the homes
of asthmatic children living in the inner city found improved daytime symptom scores in the
treatment group. On the contrary, a multifaceted environmental <strong>and</strong> educational intervention in
children with asthma living in urban environments (116) did not find the difference in asthma
severity scores, medication use, emergency department vis<strong>its</strong> or hospitalization between the
intervention <strong>and</strong> control groups. We considered overall quality of evidence supporting multifaceted
environmental interventions as very low due to inconsistency <strong>and</strong> imprecision of the results, <strong>and</strong> the
indirectness of the population, because of inappropriate baseline treatment in the majority of
patients.
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