Pattern of aeroallergen sensitivity in bronchial asthma patients: A cross-sectional study in a tertiary care centre

Abstract

INTRODUCTION: Asthma is one of the most common chronic noncommunicable diseases. Aeroallergens are often implicated in the pathogenesis of allergic rhinitis (AR) and bronchial asthma (BA). Identification of the most prevalent aeroallergens, to which the patients are sensitized, plays an important role in the diagnosis and treatment of BA. Among various diagnostic tests for detecting sensitizing allergens, the skin prick test (SPT) is a useful method to demonstrate hypersensitivity to a specific antigen. METHODOLOGY: This was a hospital-based cross-sectional observational study carried out on BA patients attending our institute during the year 2020–2021. BA patients of both sex and age between 18 and 65 years, diagnosed according to the latest GINA guidelines and gave written informed consent were included in the study. After recruitment, the participant’s detailed medical history and sociodemographic data were obtained. Total eosinophil count (TEC), serum immunoglobulin E (S. IgE), X-ray PNS, chest X-ray, and other investigations as required were done. SPT was done using 63 antigens, which included 20 pollens, 8 fungi, 5 insects, 8 dusts, 4 dander, 2 dust mites, 2 feathers, and 14 food allergens. RESULTS: Six thousand and three hundred SPTs were performed with a total of 63 allergens using the modified SPT technique. Of the 100 patients enrolled, 71% were diagnosed as BA and 29% as BA with AR. Among the study population, 44% were females and 56% were males. The majority was constituted of young adults, aged 21–30 years. More than half of the patients (68%) had their duration of disease between 1 and 5 years. Seventy percent patients reported seasonal variation in symptoms, and spring season was associated with maximum allergic exacerbations followed by winter. Significant positive reaction (≥2+) in SPT was found in 89% of patients, whereas 11% tested negative for all allergens. pollens were the most common aeroallergen group identified, whereas feathers and food allergens were the least common in the present study. Among pollen, Prosopis juliflora was the most common (24%) pollen-causing sensitization closely followed by Holoptelea integrifolia (17%) and Gynandropsis gynandra (18%). Female cockroach (37%) and mosquito (37%) were the most common insects to which the majority of the population were sensitized. Dermatophagoides farinae was accounting for 23% of positive reactions in the study population. Alternaria tenuis was the most common fungus to which 6% of the patients tested positive. House dust (17%) was the most common dust subgroup associated with positive SPT. Among danders, buffalo dander (8%) was observed to be the most common sensitizer followed by dog dander (6%). The pigeon feather was the most common feather identified. A strong positive correlation was observed between S. IgE and the number of allergens that tested positive (r = 0.489; P < 0.0001) and a strong positive correlation was observed between serum TEC and the number of allergens that tested positive (r = 0.430; P < 0.0001). CONCLUSION: Our study identified pollen as the most common sensitizing aeroallergen followed by insects. Such studies, conducted from time to time, shed light on the changing trends of the commonly prevalent allergens in a particular area. The identification of offending allergens for a patient also explores treatment options such as allergen-specific immunotherapy.

Keywords

• aeroallergens
• allergic rhinitis
• bronchial asthma
• skin prick test