Exposures to molds in school classrooms of children with asthma

BACKGROUND

Students spend a large portion of their day in classrooms which may be a source of mold exposure. We examined the diversity and concentrations of molds in inner-city schools and described differences between classrooms within the same school.

METHODS

Classroom airborne mold spores, collected over a 2 day period, were measured twice during the school year by direct microscopy.

RESULTS

There were 180 classroom air samples collected from 12 schools. Mold was present in 100% of classrooms. Classrooms within the same school had differing mold levels and mold diversity scores. The total mold per classroom was 176.6 ± 4.2 spores/m3 (geometric mean ± standard deviation) and ranged from 11.2 to 16,288.5 spores/m3. Mold diversity scores for classroom samples ranged from 1 to 19 (7.7 ± 3.5). The classroom accounted for the majority of variance (62%) in the total mold count, and for the majority of variance (56%) in the mold diversity score versus the school. The species with the highest concentrations and found most commonly included Cladosporium (29.3 ± 4.2 spores/m3), Penicillium/Aspergillus (15.0 ± 5.4 spores/m3), smut spores (12.6 ± 4.0 spores/m3), and basidiospores (6.6 ± 7.1 spores/m3).

CONCLUSIONS

Our study found that the school is a source of mold exposure, but particularly the classroom microenvironment varies in quantity of spores and species among classrooms within the same school. We also verified that visible mold may be a predictor for higher mold spore counts. Further studies are needed to determine the clinical significance of mold exposure relative to asthma morbidity in sensitized and non-sensitized asthmatic children.

Predicting food challenge outcomes for baked milk: role of specific IgE and skin prick testing

BACKGROUND

Cow's milk allergy is the most common food allergy in childhood. Many children with IgE-mediated cow's milk allergy may tolerate baked milk products, but few data exist on predictors of outcomes of baked milk challenges.

OBJECTIVE

To determine the relation of milk protein allergen specific IgE (sIgE) levels and skin prick test (SPT) wheal size with baked milk challenge outcomes.

METHODS

A retrospective medical record review was conducted of 35 baked milk challenges. SPT results, sIgE levels, demographic characteristics, and food challenge results were analyzed.

RESULTS

Thirty-five children underwent open challenges to baked milk and 29 (83%) passed. Of those who failed, 3 (50%) passed the initial clinic challenge but developed symptoms to ongoing exposure at home, days to months later. One child who ultimately failed at home required epinephrine. Compared with those who passed, children who failed were younger (median age, 8.9 and 3.7 years, respectively; P = .02). Children with a milk SPT wheal less than 12 mm were more than 90% likely to pass a baked milk challenge, and no child with a milk SPT wheal less than 7 mm failed a baked milk challenge. We were also able to establish more than 90% predictive values for passing baked milk challenges with a casein SPT wheal of 9 mm, a milk sIgE level of 1.0 kU/L, and a casein sIgE level of 0.9 kU/L.

CONCLUSION

Most children allergic to cow's milk tolerated baked milk. Milk protein SPT wheal may be more reliable than sIgE level in predicting outcomes of baked milk challenges. It is important to be aware of the possibility of late reactions to ongoing baked milk exposure.

The utility of forced expiratory flow between 25% and 75% of vital capacity in predicting childhood asthma morbidity and severity

OBJECTIVES

The forced expiratory volume in 1 second (FEV(1)) felt to be an objective measure of airway obstruction is often normal in asthmatic children. The forced expiratory flow between 25% and 75% of vital capacity (FEF(25-75)) reflects small airway patency and has been found to be reduced in children with asthma. The aim of this study was to determine whether FEF(25-75) is associated with increased childhood asthma severity and morbidity in the setting of a normal FEV(1), and to determine whether bronchodilator responsiveness (BDR) as defined by FEF(25-75) identifies more childhood asthmatics than does BDR defined by FEV(1).

METHODS

The Boston Children's Hospital Pulmonary Function Test database was queried and the most recent spirometry result was retrieved for 744 children diagnosed with asthma between 10 and 18 years of age between October 2000 and October 2010. Electronic medical records in the 1 year prior and the 1 year following the date of spirometry were examined for asthma severity (mild, moderate, or severe) and morbidity outcomes for the three age, race, and gender-matched subgroups: Group A (n = 35) had a normal FEV(1), FEV(1)/forced vital capacity (FVC), and FEF(25-75); Group B (n = 36) had solely a diminished FEV(1)/FVC; and Group C (n = 37) had a normal FEV(1), low FEV(1)/FVC, and low FEF(25-75). Morbidity outcomes analyzed included the presence of hospitalization, emergency department visit, intensive care unit admission, asthma exacerbation, and systemic steroid use.

RESULTS

Subjects with a low FEF(25-75) (Group C) had nearly 3 times the odds ratio (OR) (OR = 2.8, p < .01) of systemic corticosteroid use and 6 times the OR of asthma exacerbations (OR = 6.3, p > .01) compared with those who had normal spirometry (Group A). Using FEF(25-75) to define BDR identified 53% more subjects with asthma than did using a definition based on FEV(1).

CONCLUSIONS

A low FEF(25-75) in the setting of a normal FEV(1) is associated with increased asthma severity, systemic steroid use, and asthma exacerbations in children. In addition, using the percent change in FEF(25-75) from baseline may be helpful in identifying BDR in asthmatic children with a normal FEV(1).

Role of specific IgE and skin-prick testing in predicting food challenge results to baked egg

Previous studies suggest that children with egg allergy may be able to tolerate baked egg. Reliable predictors of a successful baked egg challenge are not well established. We examined egg white-specific IgE levels, skin-prick test (SPT) results, and age as predictors of baked egg oral food challenge (OFC) outcomes. We conducted a retrospective chart review of children, aged 2-18 years, receiving an egg white-specific IgE level, SPT, and OFC to baked egg from 2008 to 2010. Fifty-two oral baked egg challenges were conducted. Of the 52 challenges, 83% (n = 43) passed and 17% (n = 9) failed, including 2 having anaphylaxis. Median SPT wheal size was 12 mm (range, 0-35 mm) for passed challenges and 17 mm (range, 10-30 mm) for failed challenges (p = 0.091). The negative predictive value for passing the OFC was 100% (9 of 9) if SPT wheal size was <10 mm. Median egg white-specific IgE was 2.02 kU/L (range, <0.35-13.00 kU/L) for passed challenges and 1.52 kU/L (range, 0.51-6.10 kU/L) for failed challenges (p = 0.660). Receiver operating characteristic (ROC) curve analysis for SPT revealed an area under the curve (AUC) of 0.64. ROC curve analysis for egg white-specific IgE revealed an AUC of 0.63. There was no significant difference in age between patients who failed and those who passed (median = 8.8 years versus 7.0 years; p = 0.721). Based on our sample, SPT, egg white-specific IgE and age are not good predictors of passing a baked egg challenge. However, there was a trend for more predictability with SPT wheal size.

Endotoxin exposure in inner-city schools and homes of children with asthma

BACKGROUND

Endotoxins are stimulators of the immune system and, despite their potential to protect against allergy, have been associated with early wheezing and asthma morbidity.

OBJECTIVE

To compare inner-city school endotoxin exposure with home endotoxin exposure in children with asthma.

METHODS

Students with asthma were recruited from 12 urban elementary schools. Settled and airborne dust samples, linked to enrolled students, were collected from school classrooms, gymnasiums, and cafeterias twice during the academic year. For comparison, settled dust was collected once from the bedrooms of students with asthma.

RESULTS

Two hundred twenty-nine school settled dust samples and 118 bedroom settled dust samples were collected and analyzed for endotoxin. The median endotoxin concentration for school samples was 13.4 EU/mg (range, 0.7-360.7 EU/mg) and for home samples was 7.0 EU/mg (range = LLOD-843.0 EU/mg). The median concentration within each individual school varied from 6.6 EU/mg to 24.0 EU/mg. One hundred four students with asthma had matched classroom and bedroom endotoxin exposure measurements performed in the same season and demonstrated significantly higher concentrations of endotoxin in the students' classrooms (mean log value, 1.13 vs 0.99, P = .04). The median of the classrooms was 12.5 EU/mg compared with their bedrooms, with a median of 7.0 EU/mg. Within the school environment, no significant difference was seen between the fall and spring samples (mean log value 1.14 vs 1.09; P = .35).

CONCLUSION

Inner-city children with asthma were exposed to higher concentrations of endotoxin in their classrooms as compared with their bedrooms. Further studies are needed to evaluate school endotoxin exposure as a factor in asthma morbidity.

The school inner-city asthma study: design, methods, and lessons learned

BACKGROUND

Children spend a significant amount of time in school. Little is known about the role of allergen exposure in school environments and asthma morbidity.

OBJECTIVES

The School Inner-City Asthma Study (SICAS) is a National Institutes of Health (NIH)-funded prospective study evaluating the school/classroom-specific risk factors and asthma morbidity among urban children.

METHODS/RESULTS

This article describes the design, methods, and important lessons learned from this extensive investigation. A single center is recruiting 500 elementary school-aged children, all of whom attend inner-city metropolitan schools. The primary hypothesis is that exposure to common indoor allergens in the classroom will increase the risk of asthma morbidity in children with asthma, even after controlling for home allergen exposures. The protocol includes screening surveys of entire schools and baseline eligibility assessments obtained in the spring prior to the academic year. Extensive baseline clinical visits are being conducted among eligible children with asthma during the summer prior to the academic school year. Environmental classroom/school assessments including settled dust and air sampling for allergen, mold, air pollution, and inspection data are collected twice during the academic school year and one home dust sample linked to the enrolled student. Clinical outcomes are measured every 3 months during the academic school year.

CONCLUSION

The overall goal of SICAS is to complete the first study of its kind to better understand school-specific urban environmental factors on childhood asthma morbidity. We also discuss the unique challenges related to school-based urban research and lessons being learned from recruiting such a cohort.

Tree nut allergy, egg allergy, and asthma in children

BACKGROUND

Children with food allergies often have concurrent asthma.

OBJECTIVE

The authors aimed to determine the prevalence of asthma in children with food allergies and the association of specific food allergies with asthma.

METHODS

Parental questionnaire data regarding food allergy, corroborated by allergic sensitization were completed for a cohort of 799 children with food allergies. Multivariate regression analysis tested the association between food allergy and reported asthma.

RESULTS

In this cohort, the prevalence of asthma was 45.6%. After adjusting for each food allergy, environmental allergies, and family history of asthma, children with egg allergy (odds ratio [OR] = 2.0; 95% confidence interval [CI] = 1.3-3.2; P < .01) or tree nut allergy (OR = 2.0; 95% CI = 1.1-3.6; P = .02) had significantly greater odds of report of asthma.

CONCLUSION

There is a high prevalence of asthma in the food-allergic pediatric population. Egg and tree nut allergy are significantly associated with asthma, independent of other risk factors.

Characterizing the relationship between sesame, coconut, and nut allergy in children

Sesame and coconut are emerging food allergens in the United States. We sought to examine whether children allergic to peanuts and tree nuts are at increased risk of having an allergy to sesame or coconut. We performed a retrospective chart review of children who underwent skin prick testing (SPT) to sesame and coconut and identified 191 children who underwent SPT to sesame and 40 to coconut. Sensitization to sesame was more likely in children with positive SPT to peanuts (odds ratio [OR] = 6.7, 95% confidence interval [CI] [2.7-16.8], p < 0.001) and tree nuts (OR = 10.5, 95% CI [4.0-27.7], p < 0.001). Children with histories of both peanut and tree nut reaction were more likely to have a history of sesame reaction (OR = 10.2, 95% CI [2.7-38.7], p < 0.001). Children with sensitization or allergy to peanuts or tree nuts were not more likely to be sensitized or allergic to coconut. In conclusion, children with peanut or tree nut sensitization were more likely to be sensitized to sesame but not coconut. Children with clinical histories of both peanut and tree nut allergy were more likely to be allergic to sesame.

Age-specific prevalence of outdoor and indoor aeroallergen sensitization in Boston

Questions exist regarding the appropriate age for referral of an atopic child to an allergist for environmental skin prick testing. This study evaluates age-specific prevalence of sensitization to aeroallergens from infancy through adolescence. A total of 1394 patients were skin tested, with 57.2% being sensitized to at least 1 aeroallergen. In children younger than 2, the authors found that 26.5% were sensitized, including to dogs (15.5%) and cats (9.2%). Additionally, tree sensitization was demonstrated in the youngest age group (7.8% at 0-2 years; 17.1% at 2-4 years), including in 3 infants less than 1 year old. Sensitization rates to dust mites and trees were the highest in all ages above 4 years, with a peak tree sensitization of 56.4% at 10 to 12 years and a peak dust mite sensitization of 56.8% in the >12 group. Overall, the authors observed increasing sensitization rates throughout childhood for indoor and outdoor aeroallergens (P < .001). Aeroallergen sensitization begins at a young age and increases during childhood.

Pest and allergen exposure and abatement in inner-city asthma: a work group report of the American Academy of Allergy, Asthma & Immunology Indoor Allergy/Air Pollution Committee

Our work group report details the importance of pest allergen exposure in inner-city asthma. We will focus specifically on mouse and cockroach exposure. We will discuss how exposure to these pests is common in the inner city and what conditions exist in urban areas that might lead to increased exposure. We will discuss how exposure is associated with allergen sensitization and asthma morbidity. Finally, we will discuss different methods of intervention and the effectiveness of these tactics.

Sesame allergy: role of specific IgE and skin-prick testing in predicting food challenge results

There are conflicting data regarding the diagnostic value of sesame-specific IgE and sesame skin test. Currently, there are no established thresholds that predict clinical reactivity. We examined the correlation of sesame ImmunoCAP and skin-prick test (SPT) results with oral challenge outcomes in children suspected of having a sesame food allergy. We conducted a retrospective chart review of children, aged 2-12 years, receiving a sesame ImmunoCAP level, SPT, and food challenge from January 2004 to August 2008 at Children's Hospital Boston and affiliated allergy clinics. Food challenges were conducted in cases of questionable clinical history or a negative ImmunoCAP and/or negative SPT despite a convincing history. Thirty-three oral sesame challenges were conducted. Of the 33 challenges performed, 21% (n = 7) failed and 79% (n = 26) passed. A sesame-specific IgE level of > or = 7 kU(A)/L showed specificity of >90%. An SPT wheal size of > or = 6 mm showed specificity of >90%. Receiver operator characteristic (ROC) curve analysis for sesame-specific IgE revealed an area under the curve (AUC) of 0.56. ROC curve analysis for SPT wheal size revealed an AUC of 0.67. To our knowledge, this study represents the largest number of sesame challenges performed to evaluate the diagnostic value of both sesame-specific IgE and SPT. Based on our sample, both tests are not good predictors of true sesame allergy as determined by an oral challenge. We were unable to establish a threshold with a 95% positive predictive value for both sesame-specific IgE and SPT.

Skin Testing With Water Buffalo's Milk in Children With Cow's Milk Allergy

BACKGROUND: Cow's milk allergy is the most common food allergy in young children. In areas outside the United States, milk from other mammals has been studied as a possible and desirable alternative for children with cow's milk allergy. OBJECTIVES: We chose to further investigate water buffalo's milk as an alternative for cow's milk allergic children in the United States. METHODS: Children with cow's milk allergy were skin prick tested with water buffalo's milk. Additionally, subjects were followed clinically for 1 year after the test to determine how many of the subjects had persistent cow's milk allergy. RESULTS: In total, 30 children, age 8 months to 8 years, were skin prick tested to water buffalo's milk with 73% (22/30) having a positive test. All children with a negative water buffalo's milk skin test also had a negative cow's milk skin test. In follow-up, most (7 of 8) of the children with a negative skin prick test (SPT) to water buffalo's milk were found to have outgrown their cow's milk allergy. In comparison, all of the subjects with a positive skin test to water buffalo's milk had persistent cow's milk allergy. After adjusting for this, we determined that 96% (22/23) of the children with persistent cow's milk allergy were positive on skin testing to water buffalo's milk. CONCLUSIONS: In this population, the vast majority of children with persistent cow's milk allergy were positive on skin prick testing to water buffalo's milk. These results indicate that water buffalo's milk is unlikely to be a successful alternative for children with cow's milk allergy.