Washing the dog reduces dog allergen levels, but the dog needs to be washed twice a week

TiO2-Photocatalyst-Induced Degradation of Dog and Cat Allergens under Wet and Dry Conditions Causes a Loss in Their Allergenicity

Allergies to dogs and cats can cause enormous damage to human health and the economy. Dog and cat allergens are mainly found in dog and cat dander and are present in small particles in the air and in carpets in homes with dogs and cats. Cleaning houses and washing pets are the main methods for reducing allergens in homes; however, it is difficult to eliminate them completely. Therefore, we aimed to investigate whether a TiO2 photocatalyst could degrade dog and cat allergens. Under wet conditions, exposure to the TiO2 photocatalyst for 24 h degraded Can f1, which is a major dog allergen extracted from dog dander, by 98.3%, and Fel d1, which is a major cat allergen extracted from cat dander, by 93.6-94.4%. Furthermore, under dry conditions, the TiO2 photocatalyst degraded Can f1 and Fel d1 by 92.8% and 59.2-68.4%, respectively. The TiO2 photocatalyst abolished the binding of dog and cat allergens to human IgE by 104.6% and 108.6%, respectively. The results indicated that the TiO2 photocatalyst degraded dog and cat allergens, causing a loss in their allergenicity. Our results suggest that TiO2 photocatalysis can be useful for removing indoor pet allergens and improving the partnership between humans and pets.

Environmental influences on childhood asthma: Allergens

Allergen exposure is associated with the development of allergen-specific sensitization, but their relationship is influenced by other contemporaneous exposures (such as microbial exposure) and the genetic predisposition of the host. Clinical outcomes of the primary prevention studies that tested the effectiveness of allergen avoidance in pregnancy and early life on the subsequent development of sensitization and asthma published to date are inconsistent. Therefore, we cannot provide any evidence-based advice on the use of allergen avoidance for the primary prevention of these conditions. The evidence about the impact of allergen exposure among and among sensitized children with asthma is more consistent, and the combination of sensitization and high exposure to sensitizing allergen increases airway inflammation, triggers symptoms, adversely impacts upon disease control, and is associated with poorer lung function in preschool age. However, there are differing opinions about the role of inhalant allergen avoidance in asthma management, and recommendations differ in different guidelines. Evidence from more recent high-quality trials suggests that mite allergen-impermeable bed encasings reduce hospital attendance with asthma attacks and that multifaceted targeted environmental control improves asthma control in children. We therefore suggest a pragmatic approach to allergen avoidance in the management of childhood asthma for clinical practice, including the recommendations to: (1) tailor the intervention to the patient's sensitization and exposure status by using titer of allergen-specific IgE antibodies and/or the size of the skin test as indicators of potential response; (2) use a multifaceted allergen control regime to reduce exposure as much as possible; and (3) start intervention as early as possible upon diagnosis.

Avoidance of allergens as an environmental method in the prevention of inhaled allergy symptoms

Asthma and other inhaled allergies are some of the most common paediatric diseases. The association of exposure to allergens with induction and exacerbation of symptoms has been proven. The majority of allergens are permanently or periodically suspended in the air, which leads to impaired quality of life for sensitive patients. Therefore, many methods of prevention and therapy of allergic diseases have been developed. The method of allergen exposure avoidance is often the first and the most significant measure. The present research has been conducted to evaluate, based on scientific data, which measures have the most reliable evidence of effectiveness. Environmental allergen avoidance methods, despite limited evidence supporting their clinical efficacy, are listed as the main therapeutic approaches in most recommendations. The significance of the holistic approach is also emphasised: only simultaneous introduction of several avoidance methods can bring possibly beneficial effects for the patient.

The Indoor Environment and Childhood Asthma

PURPOSE OF REVIEW

Sensitization and exposure to triggers in the indoor environment, including aeroallergens, indoor air pollution, and environmental tobacco smoke, have a significant role in asthma development and morbidity. This review discusses indoor environmental exposures and their effect on children with asthma as well as environmental interventions and their role in improving asthma morbidity.

RECENT FINDINGS

Recent research has emphasized the role of aeroallergen sensitization and exposure in asthma morbidity and the importance of the school indoor environment. There is an established association between indoor exposures and asthma development and morbidity. Recent evidence has highlighted the importance of the indoor environment in childhood asthma, particularly the role of the school indoor environment. While home environmental interventions have had mixed results, interventions in the school environment have the potential to significantly impact the health of children, and ongoing research is needed to determine their effectiveness.

Prevention of Allergic Asthma with Allergen Avoidance Measures and the Role of Exposome

PURPOSE OF REVIEW

It is well known that combination of sensitization and exposure to inhaled environmental allergens is related to both the development and elicitation of symptoms of asthma and that avoidance of allergens would exert beneficial effects in the prevention and control of the disease. Other important factors include the relevance of other allergens, exposure to sensitizing agents also outside patient's home, exposure to irritants (like chemical air pollutants), and the involvement of the patient with a correct education. It is also likely that clinical phase of allergic airway disease and the degree of airways remodeling represent relevant factors for the clinical outcome of allergen avoidance procedure. We reviewed existing evidence on prevention of asthma through allergen avoidance.

RECENT FINDINGS

The management of respiratory allergy is a complex strategy (including prevention, drugs, immunological, and educational interventions). In addition, it is difficult in real life to distinguish the efficacy of single interventions. However, a combined strategy is likely to produce clinical results. A combined strategy is likely to produce satisfactory management of asthma. Allergens are an important trigger factor for the development of symptoms of respiratory allergy, and avoidance measures are able to reduce allergen levels. It is likely that clinical phase of allergic airway disease and the degree of airways remodeling represents relevant factors for the clinical outcome of allergen avoidance procedures. Considering the management of respiratory allergy is a complex strategy; it is difficult in real life to distinguish the efficacy of single interventions. However, further studies better quantifying the effects of allergens are needed.

Indoor Environmental Interventions for Furry Pet Allergens, Pest Allergens, and Mold: Looking to the Future

Over the last 2 to 3 decades, significant advances have been made in understanding the role that indoor allergen exposures play with regard to respiratory health. Multiple studies have confirmed that sensitization and exposure to indoor allergens can be a risk factor for asthma morbidity. Environmental interventions targeting key indoor allergens have been evaluated with the aims of examining their causal effects on asthma-related outcomes and identifying clinically efficacious interventions to incorporate into treatment recommendations. Historically, it appeared that the most successful intervention, as performed in the Inner-City Asthma Study, was individually tailored, targeting multiple allergens in a predominantly low-income, minority, and urban pediatric population. Recent studies suggest that single-allergen interventions may be efficacious when targeting the most clinically relevant allergen for a population. In this article, we review recent literature on home environmental interventions and their effects on specific indoor allergen levels and asthma-related outcomes.

Evaluation of Risk of Zoonotic Pathogen Transmission in a University-Based Animal Assisted Intervention (AAI) Program

Introduction: Previous studies have shown that apparently healthy animals participating in Animal-Assisted Interventions (AAI) have the potential to asymptomatically carry and even transmit zoonotic pathogens to people, which is of particular concern for therapy animal teams visiting healthcare settings. This two-part study was designed to investigate the risk of zoonotic pathogen transmission within a university-based AAI program as a combination of the prevalence of these pathogens in the animal population as well as the handlers' understanding of the risks of zoonoses in AAI and their adherence to infection control practices.

Methods: In part one of the study, AAI program records were retrospectively reviewed and infectious disease screening test results were compiled from 22 dogs and 2 cats. Screening tests for dogs and cats included a zinc sulfate fecal float, fecal culture, and nasal and perianal skin swabs for methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudointermedius (MRSP). Additional tests for cats were blood cultures for Bartonella henselae and Toxoplasmosis IgG and IgM antibody titers. In part two, a survey was conducted of 40 registered therapy animal handlers to assess knowledge, attitudes, and perceptions regarding risk of infectious disease transmission in AAI settings, including risk to the animal, the handler, and those being visited.

Results: In part one, there were 17 total positive results of the 118 infectious disease screenings performed, 14 of which were potentially zoonotic organisms. In part two of the study, a majority (70%) of respondents expressed they had no concerns regarding infectious disease transmission in AAI settings. Despite handler education and guidelines, adherence to infection control practices was lacking.

Discussion: The results of this study support prior findings that animals participating in AAI can be asymptomatic carriers of zoonotic organisms. Compliance with infection control practices and hand hygiene are paramount to mitigate risk of zoonotic disease transmission, but was inconsistent among this group of handlers. Given the popularity of AAI programs in the U.S., similar studies should be performed on a larger scale to determine the level of adherence to currently recommended practices and potential need for improvement in infectious disease control education and/or policies.

Dog and Cat Allergies: Current State of Diagnostic Approaches and Challenges

Allergies to dogs and cats affect 10%-20% of the population worldwide and is a growing public health concern as these rates increase. Given the prevalence of detectable dog and cat allergens even in households without pets, there is a critical need to accurately diagnose and treat patients to reduce morbidity and mortality from exposure. The ability to diagnose cat sensitization is good, in contrast to dogs. Component resolved diagnostics of sensitization to individual allergenic proteins will dramatically improve diagnosis. This review focuses on the current state of knowledge regarding allergies to dogs and cats, recent advances, therapies such as subcutaneous immunotherapy, and discusses important areas to improve diagnosis and therapy.

Indoor Environmental Interventions and their Effect on Asthma Outcomes

PURPOSE OF REVIEW

The use of environmental interventions to improve outcomes in asthmatics has long been an elusive goal. While numerous interventions have been studied, the results of clinical trials have been mixed. This review aims to identify combinations of interventions that have been proven to be effective and to propose a model for using them in a clinical setting.

RECENT FINDINGS

An NIH workshop emphasized a need for research to identify effective interventions for reducing indoor exposures and improving asthma outcomes. A number of innovative measures were described, though evidence supporting their use was lacking. A recent systematic review described various interventions for which evidence is available. The greatest challenge for this approach is the same as that for the medical approach to treatment: nonadherence. Given evidence for effective interventions, control of environmental exposures should lead to improved asthma outcomes. Methods to improve adherence need to be identified.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Pre-natal and post-natal exposure to pet ownership and lung function in children: The Seven Northeastern Cities Study

To evaluate the association between pre-natal and post-natal exposure to pet ownership and lung function in children, a cross-sectional study named Seven Northeastern Cities (SNEC) study was conducted. In this study, children's lung function including the forced expiratory volume in 1 second (FEV₁ ), forced vital capacity (FVC), maximal mid-expiratory flow (MMEF), and peak expiratory flow (PEF) were measured by spirometers, and pet ownership situations were collected by questionnaire. Analyzed by multiple logistic regression and generalized linear modeling, we found that for all subjects, pet exposure in the first 2 years of life was significantly associated with lung function impairment of FVC<85% predicted (adjusted odds ratio [aOR]=1.28; 95% confidence interval [CI]: 1.01, 1.63). For current pet exposure, the increased odds of lung function impairment ranged from 35% (aOR=1.35; 95%CI: 1.12, 1.62) for FVC<85% predicted to 57% (aOR=1.57; 95%CI: 1.29, 1.93) for FEV₁ <85% predicted. The in utero exposure was not related to lung function impairment. Compared with other pets, higher odds were observed among children with dogs. When stratified by gender, girls with current pet exposure were more likely to have lung function impairment than boys. It implies self-reported exposures to pets were negatively associated with lung function among the children under study.

Allergen Avoidance in Allergic Asthma

Allergic asthma is the most frequent disease among the chronic respiratory disorders in pediatric age with an important social impact. In the last years, many efforts have been made to identify effective preventive approaches to get a better control of symptoms and to obtain the best future outcomes for the patients. In patients with allergic asthma triggered by the exposure to indoor allergens, the avoidance is the first intervention to prevent the appearance or the worsening of bronchial symptoms. This review article summarized the most recent evidence from literature about the efficacy of specific control interventions for the most important allergens. Even if a wide spectrum of interventions has been suggested and may help to reduce exposure to trigger allergy for sensitized patients suffering from respiratory allergy, evidence supporting the efficacy of these approaches is still weak and subject of controversy. However, the exposure control to specific airborne allergens is still widely recommended and may be effective as part of a holistic approach to reduce the severity of allergic respiratory symptoms in sensitized individuals.

Dogs in the Workplace: A Review of the Benefits and Potential Challenges

Pet dogs, therapy dogs, and service dogs can be seen in workplaces with increasing frequency. Although dogs may provide many benefits to employees and employers, their presence may introduce additional hazards and concerns to the work environment. Therefore, decisions to accept dogs in the workplace may include many considerations including the health, safety, and well-being of employees, legal and cultural sensitivities, and animal welfare. The present paper serves to introduce the issue of dogs in the workplace and outline the potential benefits and challenges to their presence. The legal accommodations afforded to certain types of dogs in workplace settings are discussed, and the research findings pertaining to the potential benefits of dogs on human health and well-being are summarized. The paper concludes with considerations for human resource management personnel in the areas of diversity, employee relations, ethics and corporate responsibility, organizational and employee development, safety and security, and legal considerations, as well as suggested topics for future research.

Indoor and Outdoor Allergies

In last 30 to 40 years there has been a significant increase in the incidence of allergy. This increase cannot be explained by genetic factors alone. Increasing air pollution and its interaction with biological allergens along with changing lifestyles are contributing factors. Dust mites, molds, and animal allergens contribute to most of the sensitization in the indoor setting. Tree and grass pollens are the leading allergens in the outdoor setting. Worsening air pollution and increasing particulate matter worsen allergy symptoms and associated morbidity. Cross-sensitization of allergens is common. Treatment involves avoidance of allergens, modifying lifestyle, medical treatment, and immunotherapy.

Dog allergen immunotherapy: past, present, and future

OBJECTIVE

To review the published medical literature on dog allergy immunotherapy and discuss prior clinical trials, important allergens, extract specifics, and potential future treatment options for dog allergy relevant to the clinical allergist.

DATA SOURCES

MEDLINE search was performed using the terms dog, immunotherapy, and allergy limited to human studies from any period. Articles cited in selected studies also were reviewed for appropriateness of inclusion into this review.

STUDY SELECTIONS

Publications were included that were original research and fit the topic of dog allergen immunotherapy, specifically articles that investigated prior effectiveness and safety of dog allergen immunotherapy, dog extracts, identification of dog allergens, and current prescribing trends among allergists.

RESULTS

Two hundred fifteen articles were initially identified and 60 were reviewed in complete detail for inclusion in this review. The primary focus was placed on the 17 clinical trials that investigated the safety and efficacy of dog immunotherapy and the 19 studies that explored and defined the complex allergenic profile of dog extracts.

CONCLUSION

The medical literature on the use of dog extract immunotherapy in patients with hypersensitivity to dog shows poor and conflicting results of clinical efficacy, which has been attributed to poor-quality extracts and the inherent complex allergenic profile of dogs that remains without a clearly dominant allergen.

Clinical practice guideline: Allergic rhinitis

OBJECTIVE

Allergic rhinitis (AR) is one of the most common diseases affecting adults. It is the most common chronic disease in children in the United States today and the fifth most common chronic disease in the United States overall. AR is estimated to affect nearly 1 in every 6 Americans and generates $2 to $5 billion in direct health expenditures annually. It can impair quality of life and, through loss of work and school attendance, is responsible for as much as $2 to $4 billion in lost productivity annually. Not surprisingly, myriad diagnostic tests and treatments are used in managing this disorder, yet there is considerable variation in their use. This clinical practice guideline was undertaken to optimize the care of patients with AR by addressing quality improvement opportunities through an evaluation of the available evidence and an assessment of the harm-benefit balance of various diagnostic and management options.

PURPOSE

The primary purpose of this guideline is to address quality improvement opportunities for all clinicians, in any setting, who are likely to manage patients with AR as well as to optimize patient care, promote effective diagnosis and therapy, and reduce harmful or unnecessary variations in care. The guideline is intended to be applicable for both pediatric and adult patients with AR. Children under the age of 2 years were excluded from the clinical practice guideline because rhinitis in this population may be different than in older patients and is not informed by the same evidence base. The guideline is intended to focus on a limited number of quality improvement opportunities deemed most important by the working group and is not intended to be a comprehensive reference for diagnosing and managing AR. The recommendations outlined in the guideline are not intended to represent the standard of care for patient management, nor are the recommendations intended to limit treatment or care provided to individual patients.

ACTION STATEMENTS

The development group made a strong recommendation that clinicians recommend intranasal steroids for patients with a clinical diagnosis of AR whose symptoms affect their quality of life. The development group also made a strong recommendation that clinicians recommend oral second-generation/less sedating antihistamines for patients with AR and primary complaints of sneezing and itching. The panel made the following recommendations: (1) Clinicians should make the clinical diagnosis of AR when patients present with a history and physical examination consistent with an allergic cause and 1 or more of the following symptoms: nasal congestion, runny nose, itchy nose, or sneezing. Findings of AR consistent with an allergic cause include, but are not limited to, clear rhinorrhea, nasal congestion, pale discoloration of the nasal mucosa, and red and watery eyes. (2) Clinicians should perform and interpret, or refer to a clinician who can perform and interpret, specific IgE (skin or blood) allergy testing for patients with a clinical diagnosis of AR who do not respond to empiric treatment, or when the diagnosis is uncertain, or when knowledge of the specific causative allergen is needed to target therapy. (3) Clinicians should assess patients with a clinical diagnosis of AR for, and document in the medical record, the presence of associated conditions such as asthma, atopic dermatitis, sleep-disordered breathing, conjunctivitis, rhinosinusitis, and otitis media. (4) Clinicians should offer, or refer to a clinician who can offer, immunotherapy (sublingual or subcutaneous) for patients with AR who have inadequate response to symptoms with pharmacologic therapy with or without environmental controls. The panel recommended against (1) clinicians routinely performing sinonasal imaging in patients presenting with symptoms consistent with a diagnosis of AR and (2) clinicians offering oral leukotriene receptor antagonists as primary therapy for patients with AR. The panel group made the following options: (1) Clinicians may advise avoidance of known allergens or may advise environmental controls (ie, removal of pets; the use of air filtration systems, bed covers, and acaricides [chemical agents formulated to kill dust mites]) in patients with AR who have identified allergens that correlate with clinical symptoms. (2) Clinicians may offer intranasal antihistamines for patients with seasonal, perennial, or episodic AR. (3) Clinicians may offer combination pharmacologic therapy in patients with AR who have inadequate response to pharmacologic monotherapy. (4) Clinicians may offer, or refer to a surgeon who can offer, inferior turbinate reduction in patients with AR with nasal airway obstruction and enlarged inferior turbinates who have failed medical management. (5) Clinicians may offer acupuncture, or refer to a clinician who can offer acupuncture, for patients with AR who are interested in nonpharmacologic therapy. The development group provided no recommendation regarding the use of herbal therapy for patients with AR.

Environmental remediation in the treatment of allergy and asthma: latest updates

In the modern era, the prevalence of asthma and allergies are increasing. It has been speculated that environmental exposures are contributing to this rise. Several studies demonstrate that common indoor allergen exposures exacerbate asthma. Minimizing exposure to allergens and remediating the environment play a critical role in the treatment of asthma and allergies. The most effective environmental control measures are tailored multifaceted interventions which include education, thorough cleaning, using high-efficiency particulate air (HEPA) filters, integrated pest management, and maintenance of these practices.

A review on human health perspective of air pollution with respect to allergies and asthma

The increase in cases of asthma and allergies has become an important health issue throughout the globe. Although these ailments were not common diseases a few short decades ago, they are now affecting a large part of the population in many regions. Exposure to environmental (both outdoor and indoor) pollutants may partially account for the prevalence of such diseases. In this review, we provide a multidisciplinary review based on the most up-to-date survey of literature regarding various types of airborne pollutants and their associations with asthma-allergies. The major pollutants in this respect include both chemical (nitrogen dioxide, ozone, sulfur dioxide, particulate matter, and volatile organic compounds) and biophysical parameters (dust mites, pet allergens, and mold). The analysis was extended further to describe the development of these afflictions in the human body and the subsequent impact on health. This publication is organized to offer an overview on the current state of research regarding the significance of air pollution and its linkage with allergy and asthma.

A new model for environmental assessment and exposure reduction

Environmental assessment and exposure reduction are a set of diagnostic and treatment techniques that work in tandem with the traditional medical approach by reducing a patient's exposure to adverse environmental conditions as part of medical care. Assessment involves identifying the specific exposures to which a patient is sensitive and locating the corresponding contaminants in the patient's environment. This provides a more complete diagnostic evaluation of a patient's problem than could be obtained merely by examining the patient alone. Exposure reduction involves reducing the identified triggers to levels that are below thresholds that are associated with increased risk of sensitization and disease morbidity. Assessment of an environment for contaminants focuses on a chain of factors that include contaminant sources such as cockroaches, rodents, dust mites and fungi that excrete contaminants into an environment, facilitative factors such as moisture, food, water and shelter that help sources to thrive, and reservoirs where contaminants can accumulate prior to subsequent transport to occupants. By using this model to guide environmental assessments and their corresponding interventions, the root cause of health problems can be addressed, leading to improved quality of life for patients and reduced need for chronic medications.

Progress in the management of childhood asthma

Asthma has become the most common chronic disease in childhood. Significant advances in epidemiological research as well as in therapy of pediatric asthma have been made over the past 2 decades. In this review, we look at certain aspects therapy of childhood asthma, both in the past and present. Literature review on allergen avoidance (including mites, cockroach and cat), intensive therapy with β(2)-agonists in acute asthma (administering via continuous nebulization and intravenous routes), a revisit of theophylline use and its action, the use of inhaled corticosteroids in various phases of childhood asthma and sublingual immunotherapy in asthma are examined. Recent facts and dilemmas of these treatments are identified along with expression of our opinions, particularly on points of childhood asthma in the Asia-Pacific, are made in this review.

Factors associated with furry pet ownership among patients with asthma

BACKGROUND

Exposure to indoor allergens is an established risk factor for poor asthma control. Current guidelines recommend removing pets from the home of patients with asthma.

OBJECTIVES

This cross-sectional study was conducted to determine the prevalence of furry pet ownership in asthmatics compared to non-asthmatics and to identify factors associated with furry pet ownership among those with asthma. Secondary analysis assessed characteristics among asthmatics that might be associated with allowing a furry pet into the bedroom.

METHODS

Using data from The National Asthma Survey collected from 2003 to 2004, we carried out univariate and multiple regression analyses, in 2009, to identify independent predictors of furry pet ownership in asthma sufferers after controlling for potential confounders.

RESULTS

Overall, asthmatics were more likely to own a furry pet than nonasthmatic individuals in the general population (49.9% versus 44.8%, p < .001). Multivariate analysis showed that female sex, older age, white race, and high income were independent predictors of furry pet ownership among asthmatics. Additionally, 68.7% of patients with asthma who own a furry pet allowed them into their bedroom. Higher income and carrying out < or =2 environmental control practices in the home were associated with increased likelihood of allowing a furry pet into the bedroom.

CONCLUSIONS

Furry pet ownership is equally or more common among asthmatics compared to those without asthma. The majority of asthmatics with furry pets allow them into the bedroom. Recognizing and addressing these problems may help decrease asthma morbidity.

Human allergy to environmental pet danders: a public health perspective

The prevalence of human allergy to pet danders has increased rapidly over the past six decades, as a consequence of lifestyle changes that have enhanced ambient exposure to pet allergens. This is a problem of global public health importance, as the morbidity associated with allergic diseases disproportionately affects socio-economically disadvantaged populations, particularly children. Although the public often seeks advice from veterinary health-care professionals regarding healthy pet ownership practices, including strategies for reducing residential pet dander exposure, many misconceptions persist in the public domain regarding pet dander allergy, such as the belief that certain dog and cat breeds are 'hypoallergenic' due to their hair/coat type. This review considers the epidemiology of human exposure to the major cat and dog dander allergens, Fel d 1 and Can f 1 respectively, and the sensitization mechanisms to them, including the hygiene hypothesis and the putative role of bacterial endotoxin. The literature regarding primary and secondary exposures in different ambient environments is explored including threshold effects that influence allergen sensitization and elicitation of symptoms, and environmental intervention strategies that seek to reduce allergen exposure. Pet-specific factors, including the aetiopathogenesis of the several cat and dog allergens that have been characterized to the molecular level, individual animal characteristics that influence Fel d 1 and Can f 1 shedding, and pet-directed interventions intended to reduce allergen dispersal, are discussed.

New insights in allergen avoidance measures for mite and pet sensitized patients. A critical appraisal

It is widely acknowledged that avoidance of allergens such as those derived from foods, drugs, latex and stinging insects results in a complete disappearance of symptoms. By contrast, although it has been clearly shown that allergens are an important risk factor for the development of respiratory symptoms and that several avoidance measures reduce allergen levels, whether this gives clinical improvement in symptoms is debatable. Many reasons could be invoked to justify this evident discrepancy. Apart from the intrinsic methodological aspects (e.g. single or combined interventions measure, population studied, severity of respiratory symptoms, outcomes, evaluated parameters, etc.), it is important to outline that a successful approach requires that the avoided allergen is the only and real factor responsible for symptoms, the patient's education and the use of a comprehensive protocol to reduce allergen exposure. Other important factors include the involvement of the patient, the relevance of other allergens/non-specific agents, and exposure to sensitizing agents also outside patient's home. It is likely that the clinical phase of allergic airway disease and the degree of bronchial (and also nasal) remodelling, in each individual, represent relevant factors for the clinical outcome of allergen avoidance procedures. Since the management of respiratory allergy is a complex strategy (including drugs, allergen avoidance, immunological and educational interventions), it is difficult in real life to distinguish the efficacy of a single intervention in comparison to the others. A combined strategy is likely to produce better clinical results.

High allergen exposure as a risk factor for asthma and allergic disease

The association between pet ownership in childhood and subsequent asthma and sensitization is very controversial. Intriguing, but contradictory, reports have caused considerable uncertainty in parents who wish to avoid asthma and allergic disease in their children. This article argues that high allergen exposure is a risk factor for asthma and allergic disease. It describes dispersal of pet allergens in society and critically assesses epidemiological studies regarding how early exposure to pet allergens affects subsequent immunoglobulin E-sensitization and allergic diseases. Additionally, this article evaluates the effects of allergen exposure in already sensitized subjects with asthma. Cat and dog allergens are ubiquitous in society and may induce sensitization and allergic symptoms in predisposed individuals, regardless of pet ownership. This, in combination with selection mechanisms for pet ownership in families with a history of allergic diseases, makes it difficult to study associations between early exposure to pets and subsequent allergic disease. Nevertheless, exposure to pet allergens worsens asthma in already sensitized children. Thus, it is clear that clinicians should advise sensitized asthmatics that avoidance of exposure to indoor allergens is an important element in the treatment of allergic disease.

Effect of pet removal on pet allergic asthma

BACKGROUND

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.

OBJECTIVE

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

DESIGN

Prospective, nonrandomized, nonblinded observational study.

PATIENTS AND METHODS

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).

RESULTS

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.

CONCLUSION

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.

Animal danders

Animals release proteins into their surroundings through secretions, as excretions, or as dander. The quantity of dander that is dispersed by cats, dogs, or humans is sufficient to supply food for dust mites and to supply easily measurable quantities of proteins in dust. Fel d 1, Can f 1, and human IgA or IgG can be found in microgram quantities in dust samples. Allergens also can accumulate from the urine of wild or pet rodents. For cats and dogs, the accumulation of dander particles is not related to the cleanliness of the animals. All animals, including humans, provide a fully adequate supply of organic material for bacterial growth in a carpet, provided conditions are sufficiently humid. The authors' preliminary results in Virginia do not find a significant difference in endotoxin between homes with or without animals. The likely explanation for the nonallergic IgG and IgG4 response to cat, dog, or rat allergens is high exposure to proteins from these animals. If the highest levels of cat allergen in a home can result in immunologic tolerance, it is unlikely that primary avoidance would be successful at reducing exposure. The data showing that 80% of Swedish children with cat allergies never had lived with a cat imply that the concentrations of cat allergen in schools or in houses without a cat are sufficient to cause sensitization. Primary prevention would be possible only on a community basis, which is unlikely to occur. Sensitization to cat, rat, dog, or mouse allergens consistently is associated with asthma. In symptomatic children with positive skin test results, there is a strong case for allergen avoidance and a clear need for controlled trials. Controlled trials of avoidance should include houses without cats and schools. Controlling exposure to cat allergens with the cat in situ requires aggressive measures, such as removing reservoirs, washing the cat, and air cleaning. Many allergic or symptomatic children who live with a cat do not have positive skin test results or positive IgE antibodies to cats. Avoidance measures related to animals should be recommended only for individuals with positive skin test results. Increasing evidence shows that exposure to cats, dogs, rats, and other animals can induce a form of immunologic tolerance without causing allergic disease, and it is important to understand why this change occurs with dander allergens rather than with all allergens. The most probable explanations are related to the form and quantity of airborne allergens.

Pet allergen control measures for allergic asthma in children and adults

BACKGROUND

Although pet removal has been recommended in guidelines on the management of allergic asthma, pet ownership remains high in families where one or more members have an allergy to pet dander. Allergen control measures such as air filtration units placed in the homes of pet-allergic asthmatics have been used as a means of reducing allergen exposure.

OBJECTIVES

To determine the clinical efficacy of pet allergen control measures in the homes of people with pet-allergic asthma.

SEARCH STRATEGY

An electronic search of the Cochrane Controlled Trials Register was carried out. No restriction was placed on language of publication.

SELECTION CRITERIA

Randomised controlled trials comparing an active allergen reduction measure with control were considered for analysis. Participants had stable pet-allergic asthma.

DATA COLLECTION AND ANALYSIS

34 references were identified by electronic searching, but only three appeared suitable for potential inclusion in the review. Two met the inclusion criteria for the analysis. Both examined the effectiveness of air filtration units. Two reviewers extracted data independently. A limited amount of data were usable for a meta-analysis.

MAIN RESULTS

Both trials were small (n=22 and n=35). No significant differences were detected between active intervention and control on the primary and secondary outcome measures reported in the studies. Data on absence from school or work were not reported in either study. No meta-analysis could be performed due to lack of common outcomes.

REVIEWER'S CONCLUSIONS

The available trials are too small to provide evidence for or against the use of airfiltration units to reduce allergen levels in the management of pet-allergic asthma. Adequately powered trials are needed. There are no trials of other allergen reduction measures, such as pet washing or possibly pet removal.

Environmental controls in the management of allergic asthma

Environmental allergen control is one of the four primary goals of good asthma management. The American Academy of Allergy, Asthma, and Immunology has published a position statement [78] that endorses the National Asthma Education and Prevention Program management guidelines [23] and recommends that every patient with persistent asthma be evaluated for environmental allergen sensitivity. Patients who have sensitivities should receive practical advice on allergen avoidance. An accumulating body of knowledge indicates that such measures, when strictly applied for a sufficient period of time, can indeed reduce asthma symptoms, need for medication, and airway hyperresponsiveness. Ongoing prospective trials in large numbers of patients are being conducted and should enhance the ability to make proper recommendations to patients.

Controlling indoor allergens

OBJECTIVES

Reading of this article reinforces the reader's knowledge of the role of allergen exposure in relation to asthma and its severity, as well as the relevance of allergen avoidance in the treatment of asthma.

DATA SOURCES

Initial literature search for existing evidence-based guidelines, reviews, and meta-analyses was carried out, and further literature searches were performed to review individual randomized controlled trials. Evidence level was graded according to the Scottish Intercollegiate Guidelines Network recommendations.

RESULTS

There is good evidence for the link between mite and cockroach allergen exposure and sensitization, and between sensitization and asthma. For pet allergens, some studies found that exposure to pets in early life was associated with specific immunoglobulin E sensitization and allergic disease later in childhood, whereas others reported a protective effect. The effectiveness of allergen reduction in the treatment of asthma is suggested by studies in which the patients improve substantially when moved into the low-allergen environment of hospitals or high-altitude sanatoria. Because of limitations in the design of the most clinical of studies, we do not yet have a conclusive answer on the effectiveness of domestic aeroallergen avoidance.

CONCLUSIONS

Minimizing the impact of identified environmental risk factors is an important first step to reduce the severity of asthma. Although environmental control is difficult, it should be an integral part of the overall management of sensitized patients. However, what is unclear is which patients would benefit and by how much, and whether the intervention is cost-effective. These questions will be answered satisfactorily only by large randomized trials.

Methods and effectiveness of indoor environmental control

LEARNING OBJECTIVES

The purpose of this review is to describe recommended methods of decreasing exposure to indoor allergens.

DATA SOURCES

Data were obtained from published studies and reviews.

STUDY SELECTION

The reviewed studies met these criteria: 1) measurement of environmental allergens; 2) selection of participants with clearly defined allergic airway disease confirmed by detection of allergen-specific immunoglobulin E; and 3) clearly defined clinical and environmental outcomes. The studies were conducted as controlled clinical trials and the results between treated and control groups were compared with appropriate statistics.

RESULTS

The results of these studies show that installing allergen proof encasings and washing bedding frequently reduces house-dust mite exposure by 10-fold or more and significantly improves clinical measures of asthma. Washing pets reduces allergen levels temporarily. Excluding the pet from the bedroom while installing allergen-proof encasings and operating air cleaner reduces airborne allergens although having no significant effect on allergic symptoms. Cockroach populations can be controlled for over 6 months and allergens can be reduced with controlled pesticide application and cleaning, but clinical correlates have not been reported. Methods to improve adherence to environmental control measures have not been tested but effective methods can be recommended from literature on medication adherence.

CONCLUSIONS

For patients allergic to indoor allergens, reasonable recommendations include installation of allergen-impermeable encasings, frequent laundering of bedding, removing furred pets from the home, and controlling of cockroach populations with effective pesticides using the principles of integrated pest management.

The role and remediation of animal allergens in allergic diseases

Animal allergens are common causes of both acute and chronic allergic disease. The most important animal allergens are derived from mammals, principally cats, dogs, rats, mice, horses, and cows, which secrete or excrete allergens into the environment. Allergic sensitization may occur at home or in the workplace. Cat and dog allergens commonly cause allergies in the home and affect the general population. Laboratory animal handlers often have allergic reactions to rats and mice. Cow dander allergy is usually caused by occupational exposure and occurs in farmers and farm workers. Horse allergy occurs among people who regularly handle horses, either professionally or for recreational purposes. Over the past 20 years, the major animal allergens have been defined and characterized with regard to their molecular structure, immunogenicity, and environmental distribution. One remarkable finding has been the fact that most of the mammalian allergens that have thus far been cloned belong to a single family of proteins called the lipocalins. In addition to these molecular similarities, it has also been shown that most of the animal allergens are quite similar with regard to their aerodynamic properties. Although much is yet to be learned, progress is being made in our knowledge regarding the steps that may be necessary to control exposure to these allergens through environmental modifications in both homes and occupational settings. These measures include source control, air filtration devices, barrier devices, removal of carpeting and other reservoirs, and, in some cases, washing of the animal.

The role of intervention in established allergy: avoidance of indoor allergens in the treatment of chronic allergic disease

Avoidance of exposure to indoor allergens is an important element in the treatment of allergic disease. The results of several studies provide strong evidence in support of a role for allergen avoidance; however, strategies that optimize allergen reduction in houses have not been determined. Complex issues regarding the efficacy of physical and chemical measures that target house dust mite, pet, and cockroach allergens in the home are discussed. The greatest challenge is to educate allergic patients so that they can play an important role in controlling their own disease.

Pets and cockroaches: two increasing causes of respiratory allergy in indoor environments. Characteristics of airways sensitization and prevention strategies

The increasing prevalence of allergic sensitization to indoor allergens such as dust mites, pets and cockroaches is the result of the changes in indoor environments induced by human activities. The Westernized lifestyle and the increasing time spent indoors determine a reduction in natural air ventilation and, consequently, higher levels of allergen concentrations and longer exposure to allergens. The major cat allergen Fel d 1 is carried by small-dimension particles (< 5 microm diameter) that readily become airborne and persist immodified for a long time. Fel d 1 must be considered a ubiquitous allergen because it has been found in indoor environments and even in public places where a cat has never been kept. Recent research has demonstrated that clothing of cat owners may contribute to the dispersal of Fel d 1 in cat-free environments. Therefore, washing Fel d 1-contaminated clothes should be considered a simple and effective method for removing this allergen from clothing and, consequently, reducing the risk of Fel d 1 dispersion. Cockroach allergens constitute another important cause of environment-related respiratory allergy and may trigger asthma exacerbations in sensitized individuals. In the prevention of cockroach allergy, the use of chemical agents associated with an intensive vacuum cleaning of indoor environments is an important tool in removing cockroach material containing allergenic proteins. Early recognition of allergy-predisposed babies, monitoring indoor allergens and adequate strategies of allergen avoidance are likely to be important means for reducing the prevalence of bronchial asthma.