User:Jasefpotez/allergy


 * Two species of cockroach found in the United States produce clinically important allergens
 * Cockroach allergens are significant triggers of respiratory allergic diseases particularly in inner city populations. (C)
 * Cockroach infestations can occur if there is a source of water and food

At least half of inner-city homes have clinically relevant levels of cockroach allergen, and as many as 30% of suburban, middle class homes have cockroach allergen levels detected, although lower than urban homes. Household exposure to cockroaches has been shown to be associated with higher rates of asthma in inner-city areas both within the United States and in other countries.2-7
 * Cockroach allergens are prevalent in urban and suburban environments, with the highest prevalence and levels found in urban environments. Exposure is related to sensitization and asthma morbidity. (C)

The NCICAS measured cockroach allergen (Bla g 1) in collected dust of children’s bedrooms and found 85.3% had detectable levels and 50.2% had high levels (8 U/gram).8 Expanding upon these data, the Inner City Asthma Study (ICAS) found more than 50% of homes in Bronx, New York, and Chicago had Bla g 1 levels greater than 2 U/gram.9 This same study found evidence of cockroaches in 62.0%. More recently, individual city studies have shown 98% of homes in Gary, Indiana with detectable cockroach allergen5, and 56.6% of homes in New Orleans with high levels of cockroach allergen.10

The presence of cockroach allergen in not isolated to inner-city homes, but also exists in urban schools. Chew, et al. found detectable levels of cockroach allergen (Bla g 2) in 71% of dust samples from multiple samples from eleven urban high schools.11 In the analysis of schoolrooms in Detroit, Houston, and Birmingham, Alabama, Abramson, et al. found all three cities contained schoolrooms with levels of cockroach allergen exceeding sensitization thresholds.12  Similar results were found in two separate studies in Baltimore city schools.13, 14  A study of two inner city elementary schools in Minneapolis discovered the median cockroach. 15  Arbes, et al. studied multiple daycare centers in two North Carolina counties and found 52% of samples with detectable cockroach allergen.16 In inner-city populations, 30-40% of children with asthma are sensitized to cockroach, and in suburban populations, the sensitization rate is 21%. The first group to demonstrate this association was researchers with the multi-city NCICAS. Eggleston, et al. demonstrated that bedroom concentrations of Bla g 1 were related to cockroach sensitization as determined by skin testing.17  A different multicenter trial confirmed these previous findings when Huss, et al. noted individuals from homes with cockroach allergen exposure were twice as likely to have a positive skin test response to cockroach allergen.18  The association of exposure and sensitization has been documented in suburban settings as well as inner-city areas.19, 20  Recently, Chew, et al. studied home environments of inner-city children with asthma and found a dose response relationship between home Bla g 1 exposure and cockroach sensitization.21 It has also been directly linked to poorer asthma outcomes in inner-city children with asthma, including asthma-related health-care utilization. Rosenstreich, et al. were the first to show this to be the case with cockroach exposure in the NCICAS. These authors discovered that inner-city children with asthma who were sensitized to cockroach and exposed to cockroach allergen in high levels had higher asthma morbidity including more hospitalizations, more medical visits, and more reported symptoms.8  Findings from the ICAS agreed with these results in finding the combination of cockroach exposure and sensitization was association with asthma morbidity.9   Household exposure to cockroaches and mice has been shown to be associated with higher rates of asthma in inner-city areas both within the United States and in other countries.2-7  Exposure to cockroach allergen has also been shown to be associated with persistent childhood wheezing22 and severe asthma.23. A prospective study of adults with asthma in New York City did not find any association between sensitization between indoor allergens, including cockroach and mouse, and asthma morbidity.24


 * The role of cockroach allergen exposure and development of asthma and allergic diseases is unclear (D)

Cockroach allergen has been associated with sensitivity and asthma, particularly in urban environments 13, 25. Inner city children sensitized and exposed to cockroach suffer the highest morbidity 8, 9. Cockroach exposure has been shown to increase the risk of wheeze in children of atopic adults in longitudinal studies 26. Though controversial 27, this effect has been seen in both sensitized and non-sensitized children 22.

T-cell mediated allergic response to cockroach allergen correlates with exposure to elevated levels at 3 months of life 28. And, clinically, a dose response relationship has been shown between cockroach allergen exposure and asthma and recurrent wheeze in high risk children 29.