*****FROM ABC NEWS MEDICAL UNIT*****
Hi tvanhook99 and thank you for your question. Here is an answer from Mary Beth Bollinger, D.O., Pediatric asthma and allergy expert, University of Maryland Hospital for Children in Baltimore; Associate Professor of Pediatrics, University of Maryland School of Medicine:
The effectiveness of air purifiers in impacting environmental allergen levels and reducing symptoms in allergic patients is still not clear. For example, one study showed that air purifiers vs. sham purifiers could reduce cat allergen levels in bedrooms of people who are allergic to cats. However, there was no difference in symptoms in the two groups; presumably because the air purifiers could not reduce the allergen load enough to impact symptoms. And, as you point out, these purifiers can be very expensive and thus, with limited data to warrant their use, may not be worth the investment. It is very important for you to talk to your daughter's allergist about specific environmental controls based on her allergy test results. Some recommendations that could apply to all patients with asthma include use of air conditioning (making sure to clean the filter regularly) and avoidance of passive smoke exposure.
NOTE: Top medical experts on allergies answer more questions like these in the Overview section of our OnCall+ Allergy site: http://abcnews.go.com/Health/AllergiesOverview/.
*****FROM ABC NEWS MEDICAL UNIT*****