Biological and therapeutic implications of the united airways concept

The condition of the nose affects the bronchi and vice versa. Local allergen exposure leads to a generalised airway response in atopic individuals, involving the systemic circulation. Therefore, upper and lower airways need to be regarded as one functional entity. This also has implications for rhinitis and asthma therapy, providing a rationale for combined treatment of both upper and lower airways. The systemic link between the upper and lower airways may provide new opportunities for systemic treatment.