Managing Environmental Triggers for Asthma

Educational Objectives

The goal of this lecture is to reduce morbidity related to lead exposure and to symptoms of asthma through environmental management. After hearing and assimilating this lecture, the clinician will be better able to:

1. Identify common indoor environmental factors relevant to asthma management.

2. Counsel families about the most effective strategies for limiting common indoor environmental triggers for asthma symptoms.

Summary

Environmental triggers for asthma: biologic factors — dust mites, pests, pets, and mold; nonbiologic chemical factors — environmental tobacco smoke (ETS) and household chemicals (eg, fragrances, incense, scented cleaners)

National Asthma and Education Prevention Program (NAEPP; 2007): guidelines for diagnosis and management of asthma; shortened version, Guideline Implementation Panel report (GIP), listed 6 priorities; 1) use of inhaled corticosteroids as first-line controller; 2) use of written asthma action plans; 3) assessment of asthma severity; 4) assessment and monitoring of asthma control; 5) scheduling of periodic visits; 6) control of environmental exposures

Environmental triggers in the home: mold, moisture, and chronic dampness common and difficult to eradicate; mold can grow in hidden locations; requirements for growth of mold — 1) oxygen (also necessary for humans, so decreasing level not reasonable means of control); 2) food (small and difficult to control); 3) temperate environment (another necessity shared by humans); 4) water (only option for controlling mold); sources of moisture in houses — temperature difference between outside and inside (without sufficient insulation, water vapor in air condenses); also follows pipes in walls; toxicity of mold — capable of causing illness if detectable visibly or by smell; musty smell associated with mycotoxins in air that can cause lung irritation

Objective testing: inspectors use humidity monitors with prongs that penetrate walls; simple humidity monitors available for personal use (ie, measurement of differential between moisture inside and outside of house, and between different rooms); moisture concentrates in kitchens and bathrooms, and in locations in which leak has occurred (even if leak fixed); determining spore count or mold species not useful; allergy testing for mold not generally helpful because mold affects asthma via 2 pathways (ie, allergic and irritant; mycotoxins irritate sinuses and lungs; history more important than testing)

Effect of mold control on symptoms: evidence supports association between exposure to mold and symptoms of asthma; less evidence supports development of asthma as result of exposure; study — randomized controlled trial (RCT) of 62 patients; in pre-remediation phase, asthma control medications maximized; environmental remediation removed water-damaged building materials, reduced water infiltration, and improved ventilation; remediation decreased number of symptom days and exacerbations

Dust mites: most commonly encountered exposure; dust-free environment cannot be created, but control of excessive dust possible, especially with regard to clutter, carpets, and stuffed bedding; reduce clutter by using plastic bins or bags; evidence about dust mite control — mixed; in meta-analysis of 30 studies, only 4 showed association between reduction of dust mites and reduction in bronchial hyperresponsiveness; many studies addressed only one facet (eg, bedding, chemical application, carpet removal); global multifaceted approach has greatest effect

Pests: mice — animals themselves rarely seen; ask about evidence of mice, ie, droppings (typically noted near power cords or home entry points); rats — rare exposure (not as bold or common as mice); cockroaches — seen alive or dead; droppings often seen in, eg, corners; deterrents — control of entry points important since neighbors may not control pests; sealing of holes to prevent access; sealing food

Integrated pest management: does not prohibit pesticides; least toxic strategies used first; pest population reduced through setting traps, sealing holes, and educating residents about clutter, food storage, and importance of cleanliness; strategic placement of pesticides important (foggers or “bombs” effective for short time and associated with side effects); building-wide approach needed

Studies: New York City Public Housing — control group received standard pesticide application; intervention apartments treated with integrated pest management approach and had lower cockroach counts after 3 mo, sustained over 3 to 6 mo, with lower cockroach allergen levels in kitchen and bedrooms; study by Phipatanakul et al — in RCT involving 18 homes in Boston, integrated pest management (eg, filling holes, cleaning, low-toxicity pesticides, traps) reduced mouse allergens over 5-mo period; however, longer process required because mice intelligent (able to adapt to integrated pest management)

Pets: difficult discussion with families; main issue pet hair, especially in bedroom; clinician may suggest making bedroom “safe sleeping zone” (pets barred from access); however, strategy limited because allergens adheres to person; cat allergen transported into classrooms by students (>25% of classrooms may have detectable allergens); best strategy removal of pet from home; in RCT of 35 individuals with cat allergy, high-efficiency particulate air (HEPA) cleaner, mattress and pillow covers, and cat exclusion from bedroom reduced airborne cat allergen but had little effect on disease activity; treatment with intranasal steroids option when family wishes to keep cat; in RCT of active HEPA filter vs sham filter, filter produced no change in overall amount of cat and dog allergens but mild decrease in nighttime symptoms and insignificant trend toward improvement in bronchial hyperresponsiveness; pet washing decreases allergens (but bathing pet twice weekly difficult)

Nonbiologic exposures: ETS — most concerning chemical exposure; recommend quitting smoking (reducing exposure); admitted smoker typically smokes in home; suggest creating smoke-free home and car; tertiary exposure — ie, toxins from smoke that linger on clothes; in smoke-free home, suggest smokers wear “smoking jacket” outside and smoke-free jacket inside house; home-based chemical use — common; 90% of homes use chemicals that can cause illness in children; eg, cleaners, perfumes, scented objects for personal hygiene, moth balls; most potentially modifiable trigger; encourage change to nonirritating products (eg, white vinegar and baking soda for cleaning, essential oils for scent)

Key take-home messages: control mold through water deprivation; control dust by addressing clutter and stuffed bedding; ask families about pest droppings; use integrated pest management; pet exposure difficult to control; ETS best controlled by quitting smoking; minimize exposure to chemicals

The Community Guide — Asthma Control: systematic review of environmental control; strong evidence supports home-based, multitrigger, multicomponent interventions for reducing symptom days, improving quality of life and symptom scores, and reducing missed school days; Inner-City Asthma Study — followed >900 children after 1-yr intervention; children typically allergic to ≥1 indoor environmental agent; intervention associated with fewer symptom days; effect persisted 1 yr later, especially with regard to dust and cockroach allergens; expensive ($1500) but comparable in dollars per symptom day with inhaled corticosteroid

Environmental history taking: National Environmental Education Foundation provides forms for pediatric patients with asthma and tool kit for diagnosis (2-visit protocol with completion of initial history form and discussion with family; includes handouts of strategies; follow up 1-2 mo later)

Readings

Almqvist C et al: Worsening of asthma in children allergic to cats, after indirect exposure to cat at school. Am J Respir Crit Care Med 2001 Mar;163(3Pt1):694-8; Kass D et al: Reduction Effectiveness of an integrated pest management intervention in controlling cockroaches, mice, and allergens in New York City public housing. Env Health Persp 2009 Aug;117(8):1219-25; Kercsmar CM et al: Reduction in asthma morbidity in children as a result of home remediation aimed at moisture sources. Env Health Persp 2006 Oct;114(10):1574-80; National Heart Lung and Blood Institute: National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. Bethesda, MD: US Department of Health and Human Services, NIH; 2007; National Heart Lung and Blood Institute: Guideline Implementation Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. Bethesda, MD: US Department of Health and Human Services, NIH; 2007; Morgan WJ et al: Results of a home-based environmental intervention among urban children with asthma. N Engl J Med 2004 Sep 9;351(11):1068-80; Phipatanakul W et al: Effect of environmental intervention on mouse allergen levels in homes of inner-city Boston children with asthma. Ann Allergy Asthma Immunol 2004 Apr;92(4):420-5; Recer GM: A review of the effects of impermeable bedding encasements on dust-mite allergen exposure and bronchial hyper-responsiveness in dust-mite-sensitized patients. Clin Exp Allergy 2004 Feb;34(2):268-75; Sulser C et al: Can the use of HEPA cleaners in homes of asthmatic children and adolescents sensitized to cat and dog allergens decrease bronchial hyperresponsiveness and allergen contents in solid dust? Int Arch Allergy Immunol 2009;148(1):23-30; Wood RA and Eggleston PA: The effects of intranasal steroids on nasal and pulmonary responses to cat exposure. Am J Respir Crit Care Med 1995 Feb;151(2Pt1):315-20.

Disclosures

For this lecture, members of the faculty and planning committee reported nothing to disclose.

Acknowledgements

Dr. Sandel spoke at the 2016 Current Clinical Pediatrics, presented by The Barry M. Manuel Office of Continuing Medical Education, Boston University School of Medicine, Boston, MA, and held April 18-22, 2016, in Hilton Head, SC. For information about upcoming CME conferences from The Barry M. Manuel Office of Continuing Medical Education, please visit bumc.bu/edu/cme. The Audio Digest Foundation thanks the speaker and The Barry M. Manuel Office of Continuing Medical Education for their cooperation in the production of this lecture.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

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Lecture ID:

PD622902

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.