Cockroach sensitivity in Iranian asthmatic children under the age of five years/Astimi Olan Iran'li bes yas cocuklarda hamam bocegi duyarliligi.
Introduction: Exposure to cockroaches was reported to be a cause of
asthma in many parts of the world. The aim of the study was to determine
the prevalence of cockroach sensitivity in asthmatic children under 5
years of age in Iranian children with asthma.
Material and Method: Ninety two (33 female/59 male) patients were asked to complete a questionnaire covering demographic characteristics, and were subjected to skin prick testing for cockroach allergen. Blood samples were also withdrawn for assessment of total serum IgE and eosinophilia.
Results: Twenty seven percent (n=25) of subjects had positive skin test results for cockroach allergen. There were no significant correlations between the prevalence of cockroach skin test positivity in male and female children, rural and urban areas or infants under 2 years and older. The age of the youngest subject with a positive skin test for cockroach was 2 months. Moreover, the parent's level of education and the type and age of children's residence had no effect on the prevalence of cockroach skin test positivity. There was also no significant correlation between the total serum IgE and eosinophilia and the prevalence of cockroach skin test positivity.
Conclusion: Cockroach is an important source of domestic infestations in the city of Shiraz. Sensitization to cockroach allergens may develop early in life. Skin test for cockroach allergen in asthmatic children may provide information for programming environmental control strategies.
(Tur Toraks Der 2009;10:26-30)
Key words: Asthma, cockroach, children
Received: 25.12.2007 Accepted: 17.7.2008
Giris: Dunyanin pek cok yerinde hamam boceklerinin astima yol acabilecegi gosterilmistir. Bu calismanin amaci da astimi olan Iran'li cocuklarda 5 yas altinda hamam bocegine bagli astim prevelansini belirlemektir.
Gerec ve Yontem: Otuz ucu kiz, 59'u erkek toplam 92 olgu, demografik ozellikleri ve hamam bocegi duyarliligini iceren anketi cevapladi. Olgulara hamam bocegi alerjisini belirlemek icin cilt testi yapildi ve serumda total IgE ve eozinofil duzeylerine bakildi.
Bulgular: Olgularin %27'sinin (n=25) cilt testlerinde hamam bocegine karsi pozitif reaksiyon goruldu. Hamam bocegine karsi cilt testi pozitif olan en kucuk cocuk 2 aylikti. Hamam bocegi icin yapilan cilt testi taramalarinda erkek ya da kiz cocuklar arasinda, kentsel ya da kirsal yorede yasayan cocuklar arasinda ve 2 yas altinda ve ustundeki cocuklar yonunden istatistiksel duzeyde anlamli bir farklilik gorulmedi. Cocuklarin yasadigi sehrin ozellikleri ve ailenin egitim duzeyi de hamam bocegi icin yapilan cilt testinin pozitifligine herhangi bir etki yapmiyordu. Diger taraftan total serum IgE duzeyi ve eozinofili ile hamam bocegi icin pozitif cilt testi arasinda da anlamli bir iliski bulunamadi.
Sonuc: Hamam bocekleri Shiraz sehri icin ev ici salgin haline gelen onemli bir sorundur. Bu nedenle hamam bocegine duyarlilik hayatin daha erken donemlerinde ortaya cikabilmektedir. Astimli cocuklarda hamam boceklerine olan duyarliligin belirlenmesi ve cevresel kontrol stratejilerinin gelistirilmesinde cilt testleri yararli olabilir. (Tur To raks Der 2009;10:26-30)
Anahtar sozcukler: Astim, hamam bocegi, cocuklar
Gelifl Tarihi: 25.12.2007 Kabul Tarihi: 17.7.2008
Asthma in children
Asthma in children (Research)
Cockroaches (Health aspects)
Prevalence studies (Epidemiology)
|Publication:||Name: Turkish Thoracic Journal Publisher: Aves Yayincilik Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Aves Yayincilik ISSN: 1302-7808|
|Issue:||Date: March, 2009|
|Topic:||Event Code: 310 Science & research|
|Geographic:||Geographic Scope: Turkey Geographic Code: 7TURK Turkey|
The prevalence of asthma and related allergic disorders in childhood has increased considerably during the last few decades . Sensitivity to allergens is the hallmark of childhood asthma. There is evidence showing high prevalence of atopic conditions in children with asthma and a link between skin test sensitivity and severity of asthma [2-7]. Asthma prevalence, morbidity and mortality have been dramatically increasing despite the advances in medical technology and the development of new pharmacologic agents for the treatment of asthma [8-10]. Residents living in poor inner-city areas are at disproportionately high risk to asthma morbidity and mortality [11,12]. One of the reasons for this might be due to chronic exposure to indoor allergens, and high indoor allergen exposure is a significant risk factor for asthma. The major indoor allergens in the inner-city causing asthma are house-dust mites and cockroaches [13, 14]. Although it is now clear that cockroach allergen is a significant contributor to asthma [15,16], the data on the prevalence of cockroach allergy in young inner-city children are limited. Moreover, most of the recent studies have examined the prevalence of cockroach allergy in 5 year old and older children [17,18]. Children under 4 years old have the highest hospitalization rates for asthma . However, very few studies have examined the prevalence of cockroach allergy in children younger than 5 years old. Therefore this study was designed 1) To determine the prevalence of cockroach allergy in young asthmatic children, 2) To compare the prevalence of cockroach allergy in rural and urban places, and 3) To determine the association between the results of cockroach skin prick test and serum IgE, eosinophilia, parent's level of education, type of residence, or patient's sex.
MATERIAL and METHOD
We evaluated 92 patients referred to our clinic (Clinic of Allergy and Clinical Immunology, Department of Pediatrics, Shiraz University of Medical Sciences, Shiraz, Iran).
To be enrolled, children had to meet at least one of the following criteria: 1) Wheezing at least three times in their lifespan 2) Patient diagnosed with asthma by a pediatrician. 3) Prolonged cough after each upper respiratory tract infection 4) Frequent use of asthmatic drugs (salbutamol, teophyline, short courses of corticosteroids).
All patients were under the age of 5 years. Their mean age was 2.7 [+ or -] 1.4 years.
Children who had severe skin conditions precluding skin testing, had used antihistamine 72 hours before testing, had a history of anaphylaxis to previous cockroach skin testing or had severe respiratory or cardiac diseases were excluded.
As a part of the evaluation, the subject's parents were asked to complete a questionnaire that included questions with respect to their level of education, their living area (rural or urban), type and age of their residence home, presence of cockroaches in their homes, species of cockroach and parents' levels of education.
Skin testing was performed by pricking the forearm skin with a standard needle and reading the results in 15 minutes. Positive (10 mg/ml histamine base) and negative (normal saline) controls were simultaneously applied along with cockroach, cat , mite , mixed trees, mixed grasses, feather mix, aspergillum, and some food allergens including milk, egg, tomato and cacao (Stallergenes, France).
The result of a test was considered positive if it produced either a wheal with a mean diameter of at least 3 mm greater than the negative control test with flare of any size, or a wheal with a diameter of less than 3 mm and a flare with a mean diameter of at least 10 mm (20).
Total serum IgE and eosinophilia
Total serum IgE (IU/ml) was quantified by ELISA (RADIM). Allergy was not probable if serum IgE was lower than 20 IU/ml, questionable if it was between 20 to 100 IU/ml, and very probable if it was higher than 100 IU/ml. Differentiation of white blood cells was done manually. Eosinophilia was considered if the absolute count of eosinophils was over than 450 per micro liter.
The data were analyzed using Pearson Chi- Square and Fisher's Exact Test. Analysis was performed with SPSS software. A P-value of [less than or equal to]0.05 was considered as statistically significant.
Of 92 children (59 male, 33 female), 25 subjects (27.2%) had positive skin test results to cockroach allergen. Sociodemographic characteristics are shown in Table 1.
Eight of the female subjects (24.2%) and 17 of the male subjects (28.8%) had positive skin test results for cockroach ([chi square]=0.22, P=0.63).
Of the patients, 27.3% had positive skin test results to mite, 27.2% to mixed trees, 9% to mixed grasses, 18.2% to feather mix, 8.5% to cat, 9.5% to aspergillum, 8.7% to tomato, 19% to cow's milk and 17% to egg.
Seven subjects (7.6%) were sensitive to mite and cockroach together. Of cockroach sensitive patients, 28% were also sensitive to mite allergen.
Of subjects with positive results of skin tests, 21 (84%) were living in urban and 4 (16%) in rural areas. There is no difference in cockroach sensitivity between those patients living in urban and rural areas (P=0.08).
Of subjects with positive results of skin tests, 5 (20%) were living in apartments and 20 (80%) in houses. Ten (40%) subjects were living in houses newer than 10 years and 15 (60%) subjects in houses older than 10 years. Ther was no difference in cockroach sensitivity between those patients living in apartments and houses or between those patients living in houses newer than 10 years or houses more than 10 years ([chi square]=0.28, P value =0.5 and [chi square]=0.44, P value=0.5, respectively).
Eleven (12%) of the mothers had college degrees. The child of one of these mothers had a positive skin test result (9.1%) and 10 (90.9%) children had negative skin test results. There is no significant relationship between the mother's education level and results of the cockroach skin prick tests ([chi square]=2.3, P=0.3).
Seventeen (18.5%) of the fathers had college degrees. Two (11.8%) of their children had positive skin test results and 15 (88.2%) had negative skin test results. There is a relationship between father's education level and results of the cockroach skin prick tests ([chi square]=6.6, P=0.03).
Of 25 subjects with positive skin test results, 6 (24%) were [less than or equal to]2 years of age and 19 (76%) were >2 years ([chi square] =0.47, P value=0.4).
Serum IgE was measured in 80 subjects. Twenty-one (26.3%) subjects had positive skin test results. Seven of them (33.3%) had serum IgE levels above 100 IU/ml (Figure 1). No relationship was found between serum IgE levels and skin prick test results ([chi square]=0.29, P value=0.24).
Six (6.5%) subjects had eosinophilia. Two of them (33.3%) had positive skin test results. No relationship was found between eosinophilia and positive skin test results (P=0.6).
Twenty-four (96%) subjects with positive skin test results and 58 (86.6%) subjects with negative skin test results reported the presence of cockroaches in their houses. (American cockroach 14%, German cockroach 40.2%, and both species 45.1%). There is no difference in cockroach sensitivity between those patients reporting the presence and absence of cockroach in houses (P=0.27).
The prevalence of positive skin test results to cockroaches in asthmatic children under the age of five years is 27.2% in our study, which is comparable to the results of other studies. This prevalence was 29% in another study from Iran . Wilson et al  reported that 26% of the asthmatic children younger than 3 years of age had positive skin test responses to cockroaches.
[FIGURE 1 OMITTED]
Alp et al  reported that 23.8% of 63 asthmatic children younger than 4 years of age had positive skin test responses to cockroach. The prevalence of cockroach allergy was reported to range from 17% to 41% in various studies involving both children and adults [2,23,24]. Vera et al  evaluated 75 children who were not previously diagnosed as having asthma or other atopic diseases. They evaluated results of the aeroallergen skin testing and association with wheezing.
Fifteen percent of the subjects had positive skin responses to cockroaches. Cockroach sensitivity was the only allergen that correlated significantly with previous episodes of wheezing .
While Turkey is Iran's neighbour, the rate of cockroach sensitization in asthmatic children is different from that of Iran. In the study of Yilmaz A, allergies to Blatella germanica and Periplaneta Americana were reported as 11.9% and 7.4%, respectively .
The results of the present study show a trend towards association between cockroach skin test positivity and living in rural areas (P=0.08). The insignificant result could be due to the small number of the patients from rural areas in the present study (7 patients). Therefore we propose repeating this study on a larger sample size to verify if there was any association between cockroach skin positivity and the living areas. Numerous studies demonstrated that cockroach allergy was a major cause of asthma in older, inner-city children. Kang et al  reported that 76% of the houses of urban asthmatics were infested by cockroaches, and 60% had a positive skin test to that allergen. Rosenstreich et al  found that, in 476 of the inner-city children with asthma, 37% were allergic to cockroaches and a high allergen level was present in half of their bedrooms. Garcia et al  compared the cockroach sensitization rates for urban, suburban, and rural areas of Kentucky. They found that 43% of the adults and children from rural areas had skin tests positive to cockroaches compared to 41% of inner-city patients.
There was no difference in the frequencies of positive skin test responses to cockroach in infants (<2 yeas of age) and older children in our study. This finding demonstrates that the cockroach allergy can start from a very early age. However, other aeroallergens such as pollens would induce allergy after some years. In the present study the youngest subject with positive skin response was 2 months old. Skin test positivity to allergen (cockroach and dust mite) in a 4 months-old infant was reported by Vera . Because cockroach sensitization may be related to recurrent wheezing, the young age of sensitization indicates the timing at which avoidance measurements or other interventions must be performed to have any influence.
Alp et al  found that twice as many young children were sensitized to cockroach as to dust mites, whereas the prevalence of sensitization to the two allergens was comparable in older children. They suggested that not only was the cockroach the most common sensitizing allergen, but also possibly the first one to appear. Moreover it was proposed that allergen avoidance might be effective, especially in monosensitized patients.
Although boys are known to be at greatest risk for atopy in general , we found no difference between the prevalence of skin prick test positivity in male and female children. Matsui et al  reported the male sex as one of the significant risk factors for cockroach sensitization among city residents. However the small sample size of this subgroup and the fact that this was not seen in the other analyses make it difficult to draw any exact conclusions about the risk associated with male sex.
Mungan et al  found that in 206 subjects with asthma, a female predominance was observed in cockroach-sensitive patients. They reported that 44% of the atopic women and 34% of the atopic men had positive skin tests with cockroach allergen.
We found no significant relationship between the mother's education level and the results of the cockroach skin prick tests, but the father's level of education was negatively related to the skin test positivity. There was no reason for this finding, however it might be related to the major role of men in the Iranian families. A study reported that lower education level, mainly that of mothers, was one of the major risk factors for the presence of cockroach allergen .
In a study using 339 asthmatic subjects, Matsui et al  reported sociodemographic factors that decreased the risk of exposure to cockroach allergen where the family income is greater than $50,000 per year and the mother had a college degree. Our study was focused on the patients of a clinic that have an income range varying between the lowest to middle income level of society. Whether the findings of the present study can be generalized or not needs clarification.
Cockroaches spread from house to house through common walls, and the housing type has been reported to be associated with the presence of cockroach allergen [33,34]. Therefore we evaluated the association between types of houses and skin test positivity. The type and age of the houses had no effect on the results of the skin prick test responses in our study. It seems that the sewage system contributes more to the presence of cockroaches in the houses than their type or age. Cockroach allergen was reported to be common in detached houses .
Some studies reported cross-reactivity between cockroach and mite allergens [26,35] but this cross-reactivity was not observed in our study because only 7.2% of cases were sensitive to both allergens.
We found no relationship between serum IgE and the results of skin prick tests to cockroaches. However, in future, studies of whether the high serum level of IgE in some of our patients is due to parasitic infestations or not must be evaluated. It is preferable to check specific IgE antibodies to cockroaches. Higher serum IgE in asthmatic patients with positive skin test results to cockroach was reported .
Only 6 subjects in our study had eosinophilia. No relationship was present between eosinophilia and results of the skin prick tests.
One of the problems in this study was the diagnosis of asthma in children aged 5 years and younger. That is because episodic wheezing and cough are common in children who do not have asthma. In this age group, clinical judgment and evaluation of symptoms and physical examination play major roles in the diagnosis of asthma. A trial therapy with short acting bronchodilators can be helpful.
We conclude that the cockroach is an important source of domestic infestation, and cockroach sensitization is frequent in asthmatic children. Sensitization to cockroach allergens can develop early in life, even as early as 2 months of age. More than 57% of infants in the rural setting, which previously was not thought of as a high cockroach environment, had positive skin test results to cockroach. Therefore strategies to reduce exposure of children to cockroach allergen should start in infancy. It seems that the type of sewage systems in Shiraz, Iran is a significant factor contributing to an increasing presence of cockroaches in homes. Evaluation and finding of some ways to improve the sewage system, is essential. Moreover, consideration of cockroach allergen in the routine skin tests in this geographic location seems reasonable.
Special thanks for Omid Ehtemam Haghighi for his kind help.
Footnote This study was approved by the Immunology and Allergy department of Shiraz University of Medical Science.
[1.] Platts-Mills TA. The role of allergens in allergic airway disease. J Allergy Clin Immunol 1998;101:S364- 6.
[2.] Gelber LE, Seltzer LH, Bouzoukis JK, et al. Sensitization and exposure to indoor allergens as risk factors for asthma among patients presenting to hospital. Am Rev Respir Dis 1993;147:573-8.
[3.] Nelson RP Jr, DiNicolo R, Femandez-Caldas E, et al. Allergen-specific IgE levels and mite allergen exposure in children with acute asthma first seen in an emergency department and in nonasthmatic control subjects. J Allergy Clin Immunol 1996;98:258-63.
[4.] O Hollaren MT, Yunginger JW, Offord KP, et al. Exposure to an aeroallergen as a possible precipitating factor in respiratory arrest in young patients with asthma. N Engl J Med 1991;324:359-63.
[5.] Ross MA, Curtis L, Scheff PA, et al. Association of asthma symptoms and severity with indoor bioaerosols. Allergy 2000;55:705-11.
[6.] Sarpong SB, Karrison T. Skin test reactivity to indoor allergens as a marker of asthma severity in children with asthma. Ann Allergy Asthma Immunol 1998;80:303-8.
[7.] Sarpong SB, Karrison T. Sensitization to indoor allergens and the risk for asthma hospitalization in children. Ann Allergy Asthma Immunol 1997;79:455-9.
[8.] Newacheck PW, Budetti PP, Halfon N. Trends in activity-limiting chronic conditions among children. Am J Public Health 1986;76:178-84.
[9.] Weiss K, Gergen P, Waganer D. Breathing better or wheezing worse? The Changing epidemiology of asthma morbidity and mortality. Annu Rev Public Health 1993;14:491-513.
[10.] Weitzman M, Gortmaker SL, Sobol AM, et al. Recent trends in the prevalence and severity of childhood asthma. JAMA 1992;268:2673-7.
[11.] Lang D, Polansky M. Patterns of asthma mortality in Philadelphia from 1969 to 1991. N Engl J Med 1994;331:1542-6.
[12.] Weiss K, Wagener D. Geographic variations in US asthma mortality: small-area analyses of excess mortality, 1981-1985. Am J Epidemiol 1990;132:S107-S115.
[13.] Call R, Smith T, Morris E, et al. Risk factors for asthma in inner city children. J Pedaitr 1992;121:862-6.
[14.] Sarpong S, Karrison T. Sensitization of indoor allergens and the risk for asthma hospitalization in children. Ann Allergy Asthma Immunol 1997;79:455-9.
[15.] Kang B. Study on cockroach antigen as a probable causative agent in bronchial asthma. J Allergy Clin Immunol 1976;58:357-65.
[16.] Menon P, Menon V, Hilman B, et al. Skin test reactivity to whole body and fecal extracts of American (Periplaneta Americana) and German (Blatella germanica) cockroaches in atopic asthmatics. Ann Allergy 1991;67:573-7.
[17.] Sarpong SB, Hamilton RG, Eggleston PA, et al. Socioeconomic status and race as risk factors for cockroach allergen exposure and sensitization in children with asthma. J Allergy Clin Immunol 1996;97:1393-1401.
[18.] Rosenstreich D, Eggleston P, Kattan M, et al. The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma. N Engl J Med 1997;336:1356-63.
[19.] CDC. Surveillance for asthma-United States, 1960-1995. MMWR 1998;47:1-27.
[20.] Adinoff AD, Rosloniec DM, McCALL LL, et al. Immediate skin test reactivity to Food and Drug Administration-approved standardized extracts. J Allergy Clin Immunol 1990;86:766.
[21.] Farhoudi A, Pourpak Z, Mesdaghi M, et al. The study of Cockroach allergy in Iranian children with asthma. IJMS 2002;27:156-160.
[22.] Wilson NW, Robinson NP, Hogan MB. Cockroach and other inhalant allergies in infantile asthma. J Allergy Clin Immunol 1999;83:27-30.
[23.] Alp H, Yu B, Grant E, et al. Cockroach allergy appears early in life in inner-city children with recurrent wheezing. Ann Allergy Asthma Immunol 2001;86:51-4.
[24.] Call RS. Smith TF, Morris E, et al. Risk factors for asthma in inner city children J Pediatr 1992;121:862-6.
[25.] Vera MJ, Drapkin S, Moy JN. Association of recurrent wheezing with sensitivity to cockroach allergen in inner-city children. Ann Allergy Asthma Immunol 2003;91:455-9.
[26.] Yilmaz A, Tuncer A, Sekerel BE, et al. Cockroach allergy in a group of Turkish children with respiratory allergies. Turk J Pediatr 2004;46:344-9.
[27.] Kang B, Jones J, Johnson Kang IJ. Analysis of indoor environment and atopic allergy in urban populations with bronchial asthma. Ann Allergy 1989;62:30-4.
[28.] Garcia DP, Corbett ML, Sublett JL, et al. Cockroach allergy in Kentucky: a comparison of inner city, suburban, and rural small town populations. Ann Allergy 1994;72:203-8.
[29.] Sears MR, Burrows B, Flannery EM, et al. Atopy in childhood. I. Gender and allergen related risks for development of hay fever and asthma. Clin Exp Allergy 1993;23:941-8.
[30.] Matsui EC, Wood RA, Rand C, et al. Cockroach allergen exposure and sensitization in suburban middle-class children with asthma. J Allergy Clin Immunol 2003:112:87-92.
[31.] Mungan D, Celik G, Sin B, et al. Characteristic features of cockroach hypersensitivity in Turkish asthmatic patients. Allergy 1998;53:870-3.
[32.] Kitch BT, Chew G, Burge HA, et al. Socioeconomic predictors of high allergen levels in homes in the greater Boston area. Environ Health Perspect 2000;108:301-7.
[33.] Chew GL, Higgins KM, Gold DR, et al. Monthly measurements of indoor allergens and the influence of housing type in a northeastern US city. Allergy 1999;54:1058-66.
[34.] Leaderer BP, Belanger K, Triche E, et al. Dust mite, cockroach, cat, and dog allergen concentrations in homes of asthmatic children in the Northeastern United States: impact of socioeconomic factors and population density. Environ Health Perspect 2002;110:419.
[35.] Huang CH, Liew LM, Mah KW, et al. Characterization of glutathione S-transferase from dust mite, Der p 8 and its immunoglobulin E cross-reactivity with cockroach glutathione S-transferase. Clin Exp Allergy 2006;36:369-76.
Mojgan Safari (1), Reza Amin (2),Sara Kashef (2), Soheila Aleyasin (2), Maryam Ayatollahi (2)
(1) Hamadan University of Medical Sciences, Hamadan, Iran
(2) Shiraz University of Medical Sciences, Shiraz, Iran
Table 1. Sociodemographic characteristics (number) ([dagger]) * CS+ CS- Total Sex male 17 42 59 female 8 25 33 Age [less than or 6 21 27 equal to] 2 years >2 years 19 46 65 Living site urban 21 64 85 rural 4 3 7 House building apartment 5 17 22 home 20 50 70 House building's age = 20 years 10 32 42 >20 years 15 35 50 Mother's education level Primary school 12 32 44 High school 12 25 37 College degree 1 10 37 Father's education level Primary school 12 39 51 High school 11 13 24 College degree 2 15 17 * CS+= cockroach sensitivity is present ([dagger])CS-= cockroach sensitivity is absent
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