Protease-containing allergen prescribing patterns have not significantly changed from [1996] [1997] [1998] [1999] [2000] [2001] [2002] [2003] Young stage of life is a crucial period for aeroallergen sensitization, considering the immaturity of the neonatal immune system which may lead to T-cell anergy or a deviation towards Th2-type response in mice.