The early life origins can be divided into a number of phases. Early life events can lead to the development of a Th2-like environment, which is influenced by infections (Th1) rather than allergen exposure, diet, and certain respiratory infections. The tendency toward a Th2-like setting will promote the likelihood of IgE production toward environmental allergens. With sensitization, there can be the development of acute airway inflammation, then persistent inflammation, and eventually airway injury and remodeling.