Study on the Role of Alternaria alternata in the Etiology of Allergic Asthma in Patients Admitted to Loghman Hospital by using the Skin Prick Test and Solid-phase Immunoassay

The prevalence of respiratory allergies, especially those induced by fungi such as Alternaria alternata, has dramatically increased over the past decade. This increase has caused major health problems worldwide. This study aimed to investigate the role of A. alternata in the etiology of allergic asthma, by using the skin prick test and assessment of IgE specific to the fungus in the patient's sera. This study enrolled 202 patients with allergic asthma, aged 12 to 83 years. Participants included 40.1% males and 59.9% females who were enrolled after recording demographic information. A skin prick test with the whole cellextract of A. alternata was performed on the epidermis of the patient's forearms. Histamine and normal saline were used as positive and negative controls, respectively. Serum levels of IgE specific for A. alternata were measured for all patients using the ImmunoCAP Phadiatop method in which the specific A. alternata allergen cocktail that connected to the solid phase reacted to IgE antibodies in each patient's sera. Data were analyzed by analysis of variance and chi-square tests. Among 202 patients with allergic asthma, 14 (6.93%) had mild asthma, 73 (36.10%) were moderate asthmatics and 115 (56.90%) had severe asthma. In total, 14 (6.93%) patients were positive for both the skin test and IgE specific to A. alternata, 35 (17.33%) had negative specific IgE and positive skin test results, and 36 (17.82%) had a positive specific IgE and negative skin test. A total of 117 (57.92%) patients were negative for both tests. The results of this study showed the presence of IgE specific for A. alternata in 50 of 202 (24.75%) patients diagnosed with allergic asthma. The skin prick test was successfully used as a screening test. The results were further confirmed by solid-phase immunoassay of the IgE specific for A. alternata crude allergenic extract.