Epidemiology of the Relationship between Exposure to Indoor Allergens and Asthma

Abstract

A very high prevalence of immediate hypersensitivity to common indoor allergens can be demonstrated among children and young adults, with asthma. Recent progress in the immunochemistry of cat, dust mite and cockroach allergens has made it possible to measure exposure to these allergens and to start to define threshold levels of exposure which increase the risk of sensitization and symptomatic asthma. Indeed, it is already clear that exposure to >2 μg group I dust mite allergen (or 100 mites) per gram of dust increases the risk of children developing sensitization and asthma. Furthermore, from studies on patients presenting to emergency rooms with asthma, it is clear that the risk of sensitization to allergens derived from cats or cockroaches or grass pollen is restricted to patients who are exposed to high levels of these allergens. Given the increasing morbidity and mortality of asthma it is clear that therapeutic efforts should be focused on identifying relevant allergens and advising patients about techniques for reducing exposure.

Seasonal Variation of Skin Reactivity and Specific IgE Antibody to House Dust Mite

“…12,13 In this study, house dust mite allergen levels reached a peak level in August and September, and then significantly decreased in November and December to less than 2 g/g of dust which is a threshold for sensitization to house dust mite suggested by Platts-Mills. 14 These changes paralleled changes in relative humidity as previously described. 3,12 Our findings of significant decrease in house dust mite allergen levels in winter were comparable to results of a study in Japan.…”

Exposure to house dust mite allergens and the clinical activity of asthma

“…Thus in a group of individuals with similar levels of IgE antibodies, some will experience symptoms only if they are exposed to high levels of allergens, whereas others require very low exposure to maintain symptoms; that is, the level of exposure necessary to induce and maintain airway inflammation, BHR, and symptoms varies over a wide range. 39 In conclusion, in patients with mite-sensitive asthma there is a dose-response relationship between the level of exposure to Group 1 and Group 2 house dust mite allergen and disease severity and clinical activity (as measured by level of BHR, PEFR variability, and pulmonary function testing).…”

Differential allergy responses toMetarhizium anisopliaefungal component extracts in BALB/c mice

“…In addition to the adverse health effects caused by asthma, the economic burden was estimated as 12.7 billion dollars in the United States for 1998 (Weiss and Sullivan, 2001). The indoor environment is thought to have some role in this increased incidence because children now spend 90-95% of their time indoors (Platts-Mills, 1995) and steps to conserve energy have greatly reduced dilution of indoor air by outdoor air. Furthermore, children exhibiting the most severe manifestations of asthma usually have a clear allergic component, with symptoms that begin in early life, and continue through adolescence and into adulthood.…”