Aeroallergen sensitization in childhood is strongly associated with the development of rhinitis and subsequent asthma during childhood and teenage years, according to a study published in The Journal of Allergy and Clinical Immunology.  Allergen sensitization is a process by which the human immune system produces antibodies in response to allergens in its environment. The researchers wrote that they analysed data from 1,510 children who participated in skin prick tests and a questionnaire about allergic diseases at median ages of 8, 12 and 19 years and found that the prevalence of allergic sensitization increases with age.