Asthma is a chronic inflammatory disease characterized by swelling and narrowing of the airways, leading to symptoms like wheezing, coughing, and shortness of breath. Nasal congestion, commonly known as a stuffy nose, involves inflammation of the nasal lining that blocks the passage of air. These two conditions are frequently linked, with studies showing that up to 80% of people with asthma also experience chronic congestion or rhinitis.
The Unified Airway: Why Asthma and Nasal Congestion Coexist
The respiratory system, from the nostrils down to the smallest air sacs in the lungs, is functionally connected, a concept known as the “unified airway”. The lining of the upper airway (nose and sinuses) and the lower airway (bronchial tubes) share a similar cellular structure and react to irritants and allergens in a comparable way. This commonality explains why inflammation in one area can easily trigger inflammation in the other.
Inflammation is driven by shared chemical messengers, particularly signaling proteins called cytokines, such as Interleukin (IL)-5 and IL-13. These substances are released in the nose in response to triggers and can travel through the bloodstream or via post-nasal drip to the lower airways, initiating or worsening the inflammatory response. This unified pathological process means that rhinitis, which causes nasal congestion, contributes to the overall burden of airway disease experienced by a person with asthma.
How Nasal Congestion Impacts Asthma Control
Nasal congestion directly harms asthma control by obstructing normal nasal breathing, forcing the individual to switch to mouth breathing. The nose performs several protective functions, including filtering out allergens and particulate matter, warming cold air, and humidifying dry air before it reaches the sensitive lungs. Breathing through the mouth completely bypasses this natural air conditioning and filtration system.
When cold, dry, and unfiltered air enters the lower airways directly, it irritates the already hyper-responsive bronchial tubes. This irritation can trigger bronchospasm, the sudden tightening of the muscles around the airways, leading to acute asthma symptoms. Mouth breathing also reduces the intake of nasal nitric oxide, a gas naturally produced in the sinuses that helps dilate blood vessels and improve oxygen absorption in the lungs.
Management Approaches for Upper and Lower Airway Symptoms
Effective management of co-occurring congestion and asthma requires a comprehensive, coordinated strategy that addresses both the upper and lower airways simultaneously. Pharmacological treatment for the nasal symptoms often involves intranasal corticosteroids (INCS), which are highly effective because they directly target the underlying inflammation in the nasal passages. These nasal sprays reduce swelling and congestion, thereby encouraging a return to beneficial nasal breathing.
Oral second-generation antihistamines are frequently used for milder, intermittent allergic rhinitis symptoms, though for more persistent congestion, INCS are generally preferred. Another class of medications, leukotriene receptor antagonists, can be effective as they block inflammatory mediators that contribute to both nasal and bronchial symptoms. Decongestants can offer short-term relief, but they should be used sparingly, as prolonged use can cause a rebound effect that worsens congestion.
Non-pharmacological methods also play an important role in controlling upper airway symptoms. Saline nasal rinses or washes help flush out thick mucus, irritants, and allergens from the nasal passages, physically reducing the inflammatory load. Environmental control measures, such as using air filters and frequently washing bedding to minimize exposure to dust mites and pet dander, help reduce the triggers that initiate the inflammatory cascade.