***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Exposure to cat and dog allergens is very common in the Western World and is a serious cause of asthma in sensitized subjects . OBJECTIVE We sought to study the clinical effects of air cleaners in living rooms and bedrooms of asthmatic children sensitized to cat or dog allergens . METHODS Twenty asthmatic children sensitized to pet allergens ( cat/dog ) and with an animal at home participated in a double-blind , placebo-controlled , cross-over study in which the effects of air cleaners placed in the living room and bedroom for 3 months were compared with the effects of sham air cleaners . Before and after each study period , lung function , airway hyperresponsiveness ( adenosine monophosphate ) , and peak flow variation were recorded . Cat and dog allergen levels were assessed in the filters of the air cleaners . RESULTS After a 3-month intervention with active air cleaners , airway hyperresponsiveness decreased significantly , showing a 1.2 doubling dose increase of PC(20 ) adenosine ( P = .003 ) . Peak flow amplitude also decreased ( P = . 045 ) . Substantial amounts of airborne cat and dog allergen were captured by the air cleaners in living rooms and bedrooms as well . Allergen levels in floor dust were not changed . CONCLUSION In young asthmatic patients sensitized and exposed to pets in the home , application of air cleaners in living rooms and bedrooms was accompanied by a significant improvement in airway hyperresponsiveness and a decrease in peak flow amplitude The effects of supplementary computer instruction in house dust mite-avoidance measures on adherence to implementing measures , on home dust mite-allergen levels , and on symptomatology were investigated in 52 adult patients with mite-associated asthma . Twenty-six patients received conventional instruction ( counseling and written instruction ) and the other 26 patients received conventional plus 22 minutes of interactive computer-assisted instruction . Instructions were aim ed at mite-avoidance measures . Pre- and postinstruction dust sample s were collected , and adherence was monitored . All patients kept symptom diaries twice a day . Patients ' progress was followed for 12 weeks , and all patients completed the study . Adherence , number of observed and self-reported mite-avoidance measures implemented after visit , was higher for the computer group ( p = 0.023 ) . The computer-instructed group achieved significantly lower levels of mite allergen in bedroom carpets ( p = 0.004 ) with mean levels of mite allergen declining from 6.5 + /- 7.6 to 2.2 + /- 4.3 micrograms/gm of dust ( two-site monoclonal antibody assays ) , whereas levels for the conventional-instructed group did not change . Moreover , by study weeks 9 and 10 , the computer-instructed group was significantly less symptomatic ( p = 0.033 ) . Mean symptom scores for this group decreased from 12.4 to 7.7 , compared with 16.4 to 14.3 . Conventional instruction supplemented with computer instruction is suggested in mite education To evaluate the effect of a room high-efficiency particulate air ( HEPA ) cleaner on cat-induced asthma and rhinitis , 35 cat-allergic subjects who were living with one or more cats were studied in a double-blind , placebo controlled trial . After a 1 mo baseline period , subjects ' bedrooms were equipped with an active or placebo air cleaner for the following 3 mo . Evaluations included monthly measurement of cat-allergen levels , daily morning , afternoon , and nighttime nasal- and chest-symptom scores , twice-daily measurement of peak-flow rates , daily medication scores , monthly spirometry , and methacholine ( MCh ) challenge testing before and after the study . Airborne allergen levels were reduced in the active-filter group as compared with the placebo group ( p = 0.045 ) . However , no differences were detected in settled-dust allergen levels ( p = 0.485 ) , morning , afternoon , or nighttime nasal-symptom scores ( p = 0.769 , 0.534 , and 0.138 ) , chest-symptom scores ( p = 0.388 , 0.179 , and 0.215 ) , sleep disturbance ( p = 0.101 ) , morning or afternoon peak-flow rates ( p = 0 . 424 and 0.679 ) , or rescue medication use ( nasal , p = 0.164 , chest , p = 0.650 ) , respectively . Although the combination of a HEPA room air cleaner , mattress and pillow covers , and cat exclusion from the bedroom did reduce airborne cat-allergen levels , no effect on disease activity was detected for any parameter studied BACKGROUND In Atlanta , as in other major urban areas of the United States , asthma is a leading cause of school absenteeism , emergency department use , and hospitalization . Recent guidelines for asthma management recommend reducing exposure to relevant allergens , but neither the feasibility nor the efficacy of this form of treatment has been established for children living in poverty . OBJECTIVE We sought to investigate allergen avoidance as a treatment for asthma among inner-city children . METHODS One hundred four children with asthma living in the city of Atlanta were enrolled into a controlled trial of avoidance without being skin tested . The children were r and omized to an active avoidance group , a placebo avoidance group , and a second control group for which no house visits occurred until the end of the first year . Avoidance included bed and pillow covers , hot washing of bedding , and cockroach bait .  Eighty-five children completed the study , and the outcome was measured as unscheduled clinic visits , emergency department visits , and hospitalization for asthma , as well as changes in mite and cockroach allergen levels . RESULTS There was a significant decrease in acute visits for asthma among children whose homes were visited ( P < .001 ) . However , there was no significant difference between the active and placebo homes either in the effect on asthma visits or in allergen concentrations . When the children with mite allergy were considered separately , there was a significant correlation between decreased mite allergen and change in acute visits ( P < .01 ) . The avoidance measures  for cockroach allergen appeared to be ineffective , and the changes observed did not correlate with changes in visits . CONCLUSIONS Applying allergen avoidance as a treatment for asthma among children living in poverty is difficult because of multiple sensitivities and problems applying the protocol s in this environment . The current results demonstrate that home visiting positively influences the management of asthma among families living in poverty . Furthermore , the results for children with mite allergy strongly suggest that decreasing relevant allergen exposure should be an objective of treatment in this population This study was design ed to assess the effectiveness of a high-efficiency particulate air ( HEPA ) filter in alleviating  allergic respiratory symptoms . Thirty-two patients were studied who had symptomatic perennial rhinitis and /or asthma during the fall and winter months and had a positive skin test with house dust or house dust -- mite extract . An ENVIRACAIRE room air cleaner was placed in the bedroom for 8 weeks . In a r and om manner , the active filter was used for 4 weeks and a blank filter for 4 weeks . There was an average 70 % reduction in the particulate matter greater than or equal to 0.3 micron with the HEPA filter . In a double-blind design , results were assessed by analysis of the patients ' symptom/medication scores and subjective evaluation . For the total study , there was no difference in the total symptom/medication scores or individual symptom scores during the placebo and active-filter periods . Analysis of the last 2 weeks of each filter period in which respiratory infection was absent demonstrated definite differences in total and individual symptoms , suggesting active-filter benefit . Patients ' subjective responses also suggested benefit from the filter . The overall impression is that the HEPA filter can reduce allergic respiratory symptoms Recommendations for allergen avoidance or allergen reduction measures play an important part in the treatment of allergic asthmatic patients . The purpose of this study was to test recently developed air-cleaners with respect to their capacity to capture airborne allergen particles and to improve clinical parameters of asthmatic patients sensitized to aeroallergens . Forty five allergic asthmatic patients were studied in a double-blind procedure for 6 months . The patients were divided into three groups of 15 patients . In Group 1 , the intervention consisted of the application of active air-cleaners in living-rooms and bedrooms . In Group 2 , placebo air-cleaners were used in combination with allergen-impermeable mattress covers . In Group 3 , the same intervention was performed as in Group 2 but with active air-cleaners .  Allergen levels in mattress and floor dust were measured before , and 3 and 6 months after the interventions . After 6 months , the air-cleaners were dismantled and the filters were analysed for the amount of dust collected and allergen content . Immunological and lung function parameters were measured before , and 3 and 6 months after the interventions . Considerable amounts of airborne dust and allergenic particles were captured in the filters of the air-cleaners . Up to the 18.9 g of dust , 4,513 ng of house dust mite allergen , Der p 1 , and 50,000 mU of cat allergen , Fel d 1 , ( in houses with cats ) were collected by air-cleaners in living-rooms . Only in Group 3 ( in which both active air-cleaners and mattress covers were used ) was a small ( less than 1 doubling dose ) but statistically significant improvement of provocative concentration of histamine causing a 20 % fall in forced expiratory volume in one second ( PC20 ) observed ( from 5.96 to 9.02 mg x mL(-1 ) ) . The amount of dust and house dust mite allergen collected in the filters was significantly correlated with an improvement of peak flow variation . In combination with other allergen avoidance measures , the examined air-cleaners can contribute to diminished allergen exposure and improvement of airway hyperresponsiveness in asthmatic patients A new , portable laminar air-flow filter ( Enviracaire ) was tested on 13 asthmatic children , using a double-blind single crossover study . There was a statistical improvement in symptom scores during filter use ; however , peak flows did not improve significantly . The authors feel this method of avoiding indoor airborne irritants is useful and warrants further study The efficacy of an air‐cleaning device equipped with a high efficiency particulate air ( HEPA ) filter ( without further avoidance measures ) was studied in patients allergic to house dust mite . The effects of the air‐cleaner on indoor Dermatophagoides sp. levels , symptom score and bronchial hyperresponsiveness in nine mite‐allergic patients were assessed using a cross‐over controlled study . No significant effect was demonstrated on indoor Dermatophagoides sp. levels when comparing the period of air‐cleaner activity ( 2 months ) with the control period ( 2 months ) . The Dermatophagoides sp. levels in the houses studied were lower than the risk level for asthmatic attacks , making it difficult to assess any effect on asthma ; however , neither bronchial hyperresponsiveness nor rhinitis symptom score were changed by air‐cleaner activity . During the trial period , however the mean level of Dermatophagoides sp. allergen in the houses changed spontaneously from 4.4 Hg/g ( mean level in the first 2 trial months ) to 1 . 75 μg/g of dust ( second 2 months ) ( P < 0.05 ) . Owing to this change , the mean rhinitis symptom score also decreased ( P < 0.05 ) , even if no significant correlation was demonstrated ( r = 0.4 P= 0.089 ) . HEPA filter air‐cleaners appear insufficient as substitutes for st and ard avoidance measures in mite allergic patients 
    Output:
    
No significant differences were detected between active intervention and control on the primary and secondary outcome measures reported in the studies .
There are no trials of other allergen reduction measures , such as pet washing or possibly pet removal