The impact of age, gender, family history of allergy, clinical symptoms, and duration of illness on flare diameter of skin prick test

Introduction: Skin prick test (SPT) is a method for diagnosing IgE-mediated allergen sensitization. Although the sensitivity and specificity are quite good, false positive and false negative results are possible. The diameter of the wheal and flare of each allergen can affect the skin prick test measurement, especially if the results of the examination overlap. Because of the usage of the SPT and the emphasis on quality control of health services recently, several variables that can affect the results of SPT must be considered. This study aims to analyze the effect of age, gender, family history of allergy, clinical symptoms, and illness duration on SPT's flare diameter. Method: This is a cross-sectional study conducted from 2015 to 2020 in Surabaya, Indonesia. Children with possible allergies were tested with a skin prick test at the allergy immunology outpatient clinic of the Dr. Soetomo General Academic Hospital. Inclusion criteria were ≤ 18 years old children, possibly diagnosed with allergies, who had skin prick test. Children with incomplete medical record data were excluded.  The Chi-square test or Fisher exact test to determine the relationship between the independent and dependent variables for nominal data. The p-value was declared significant if P<0.05 to determine the effect between variables on flare diameter on skin prick test. We use SmartPLS to analyse the relationships simultaneously to compare relationships with the regression analysis. Result: Age, gender, clinical symptoms, and duration of illness did not show a significant effect. In contrast, the flare diameter determined by SPT and the presence of an allergic family had a significant correlation (p = 0.017). Therefore, the appropriate distance between allergens must be specified to prevent overlap of SPT flare diameters. Conclusion: Member of family allergy affects the diameter of the flare on skin prick test.