Viral respiratory infections can increase asthma symptoms in many patients. Although the mechanisms of these effects are not fully established, there is evidence that respiratory viruses can promote some components of allergic inflammation. In this regard, there is evidence that rhinovirus respiratory infections can lead to the development of late allergic reactions to inhaled allergen. This change in response to inhaled allergen supports the possibility that some respiratory infection will promote bronchial inflammation and may be a factor for increased wheezing with respiratory infection.