K‐means cluster analysis of characteristic patterns of allergen in different ages: Real life study

BACKGROUND: Atopy varies in people of different ages owing to different physical conditions and exposure to allergens. We aimed to cluster ages based on atopic severity using K‐means cluster analysis and identify atopic incidence, severity, as well as the association among peripheral eosinophils, IgE and sensitisation. METHODS: Consecutive patients (n = 7654) with allergic symptoms and undergoing allergen‐specific IgE tests were included from 2013 to 2017. Age, sex, specific‐IgE, peripheral eosinophil counts and total‐IgE were collected. RESULTS: Five age categories were identified: 1–17, 18–36, 37–52, 53–69 and 70–100 years. The incidences of atopy and poly‐sensitisation decreased with increasing age. Similar trend was observed for aeroallergens, egg and milk but not for peanuts, soy or seafood. Dust mites remain the crucial factor bothering patients with allergic symptoms, especially for children and adolescents. In patients aged <52 years, sensitisation to aeroallergens was more prevalent than food. In group 37–52 years, incidence of females' atopy was higher than that of males. The overlap of atopy, high eosinophils, and high total‐IgE was found in only 19.18% of patients. The trend of allergen‐test positivity is not parallel to total IgE and peripheral eosinophil counts. CONCLUSION: Age‐grouping based on cluster analysis helps to find the changes in atopic status and distribution of sensitised allergens with age. Allergen tests are still necessary in the clinical diagnosis and treatment. An innovative exploration of the influence of age and allergens on total‐IgE and eosinophil counts is helpful for the development of bio‐targeted precision therapy. CLINICAL TRIAL REGISTRATION: ChiCTR2300067700.