The Study of Cockroach Allergy in Iranian Children with Asthma

Background: Asthma is the most common chronic disease of childhood. Exposure to allergens plays an important role in asthma. Recently, cockroach has attracted attentions as an important allergen. Objective: To evaluate cockroach allergy in Iranian children with asthma. Methods: 100 children with asthma were studied. After determination of asthma severity, serum total IgE and blood eosinophils were measured.  The patients were then skin prick tested with cockroach (Blattella germanica) and some common aeroallergens and food allergens.  According to cockroach skin prick test (SPT) results, the patients were divided into two groups (sensitive and non-sensitive) and compared. Results: Positive SPT for cockroach was detected in 29% of patients.  Cockroach sensitive group had a more severe asthma (p<0.02).  Asthmatic patients with cockroach allergy had perennial symptoms (p<0.05).  A remarkable number of sensitive patients were born in winter (p<0.05).  Eosinophilia was more common in sensitive group (p<0.02) and they had a higher level of serum total IgE (p<0.04). Conclusion: The prevalence of cockroach allergy was near to other common aeroallergens.  Cockroach sensitive group had perennial symptoms, which are compatible with other indoor allergens.  Cockroach allergy was more prevalent in children born in winter.  May be these children are kept at home during their first months of life and are more exposed to cockroaches.  The higher prevalence of eosinophilia and higher IgE level in sensitive group may be the reasons of more severe asthma in this group.