Signals from the paranasal sinuses
This illustration shows how biochemical or neurogenic signals from the paranasal sinuses can affect the airways, triggering an asthma attack. The sinuses may become obstructed and infected during respiratory tract infections, thus producing these signals. Acute or chronic sinusitis has been recognized as a common trigger of asthma attacks. In those situations, pharmacological treatment of asthma is not effective unless the sinusitis is treated effectively.
Illustration by Nick Lang