Introduction

Nasal congestion occurs when the inner side of your nasal passages becomes irritated due to swelling and additional mucus production, leading to congestion and difficulty in breathing. If not treated correctly, this may lead to further conditions such as sinusitis, nasal polyps, or even otitis media.¹

Nasal congestion is most commonly caused by rhinitis, either allergic or non-allergic. Allergic rhinitis or hay fever is an immune-system reaction to particulate air irritants triggered by pollen, dust mites, mould spores, or animal dander. For non-allergic rhinitis, the inflammation may be an ongoing, low-grade reaction that results in fluid leaking out of the nasal tissues, leading to swelling. The most common factors that induce nasal congestion include environmental ones such as smoke, stress, spicy foods, medications, hormonal changes such as pregnancy, and infections such as the common cold or sinusitis. Congestion can also be caused by swollen adenoids, the glands behind the nasal passages that trap germs.¹

Recent data suggest that even brief secondhand smoke exposure (SHS) increases nasal congestion, particularly among those with rhinitis.² SHS exposure provokes subjective nasal symptoms, urinary nicotine metabolites, and tobacco-specific nitrosamines but does not change nasal nitric oxide levels.²

Types of smoke exposure

Tobacco smoke

Research has shown that tobacco smoke, through the action of smoking or second-hand smoke, does serious damage to our sinuses, especially for those with chronic rhinosinusitis (CRS). Smokers are at a higher risk of acquiring CRS, with increased risk depending on the number of cigarettes one smokes. Apart from its irritating action on nasal passages, tobacco smoke suppresses the body's defences against infection, leading to the impairment of olfaction (smell). Children, in particular, will develop severe sinus problems if they are exposed to secondhand smoke. 

Based on older studies, the outcomes of sinus surgery for smokers seemed very poor, but newer studies suggest that the procedure produces similar results for light to moderate smokers as it would for non-smokers. However, there tend to be more complications for heavy smokers. On a positive note, it is important to consider that reducing smoke exposure through quitting smoking or avoiding secondhand smoke can make quite a difference in sinus health and make living with CRS more manageable.³

Environmental smoke

Wildfires

It has been documented that serious health implications can arise from wildfire smoke, and these are increasing in frequency and intensity due to climate change. The chemical composition of wildfire smoke is highly variable and complex, depending on factors like vegetation type and meteorological conditions, which makes studying and modelling its effects very difficult. Current research underlines that wildfire smoke has a very profound impact on respiratory health. It positively correlates with emergency room visits and hospitalisations due to asthma and chronic obstructive pulmonary disease (COPD). 

However, health effects related to the cardiovascular system are less clear. While some studies did not find a significant increase in cardiovascular events during wildfires, others suggest an association. Moreover, the long-term health effects of exposure to smoke resulting from wildfires, particularly in children, require further research. Generally speaking, the health implications of wildfires must be considered for public health strategies, as they are steadily on the rise.⁴

Air pollution

There is emerging evidence that air pollution exposure plays an important role in the development and exacerbation of CRS, which is a common and debilitating sinus disease. Studies suggest a positive association between the levels of air pollution, especially fine particulate matter, and the risks of CRS development, with possible worsening symptoms within existing ones.⁵ 

Some of these studies discussed how exposure to air pollutants was related to the alteration in composition both at the level of sinus tissue and bacterial communities among CRS patients. Interestingly, the effects of air pollution appeared to differ between subtypes of CRS, namely those with and without nasal polyps.⁵ 

While this calls for further studies that comprehensively explain how air pollution affects CRS through specific pathways, these findings still point to the negative impacts of poor air quality on the health of the upper respiratory tract. This underlines the paramount necessity of air quality improvement initiatives that could lead to wide-ranging benefits for CRS patients and also to the health of the general population.⁵

Vape and e-cigarette smoke

A recent study tested the hypothesis that e-cigarette use alters the immune response to respiratory viral infection, in this case, influenza. It exposed e-cigarette users, cigarette smokers, and nonsmokers to a live-attenuated (low-level effect) influenza virus. Results showed that e-cigarette users had significantly differing nasal immune responses than controls, including reduced levels of influenza-specific IgA (an antibody protecting the respiratory tracts) and contrasting gene expression in immune function-associated genes. 

Notably, e-cigarette users had greater suppression of immune genes than smokers. Therefore, this would suggest that e-cigarettes reduce the body's defence against respiratory viruses, making them a public health concern in this era of flu season and pandemics.⁶

Mechanism of smoke-induced nasal congestion

Tobacco smoke is very injurious and has grave implications for the nasal passages and sinuses. Once inhaled, the chemicals within the smoke irritate the tender lining of the nose and inflame it, causing the tissues in the nose to swell up. This also triggers the body's natural defence mechanisms, resulting in the production of mucus while the nasal passages attempt to trap and expel these foreign particles. 

The accumulation of mucus may block the nasal passages, causing congestion and impairment in breathing. It has been shown in studies that both active smoking and passive smoke exposure enhance the risk for chronic rhinosinusitis. 

Smoke interferes with the normal movement of cilia within the nasal passages that aid in the cleaning of mucus along with other debris. This can lead to chronic inflammation of the mucous membranes, persistent infection, and changes to the nasal and sinus tissues that may require interventions for life.³

Vulnerable populations

Children

A research study followed the illnesses of children who had been hospitalised for community-acquired pneumonia (acquired outside a hospital) and determined that those children who lived in a home with two or more smokers were more seriously ill. In this study, 35.4% of the 2,219 children studied were exposed to secondhand smoke. 

Children of families in which two members smoked had longer hospitalisations, with a median of 70.4 hours, and 25.2% were admitted to intensive care compared to 20.9% of children not exposed. In contrast, children exposed to only one smoker did not differ significantly from unexposed children in either outcome. These findings underscore the dramatic health risks of SHS for children and the critical requirement for sustained public health efforts to reduce smoking in homes to protect children's health and well-being.⁷

Elderly

Another study eloquently demonstrated that wildfire smoke has increased catastrophic impacts on the elderly. More specifically, older adults faced worse health consequences from wildfire smoke exposure. The findings revealed that among the elderly exposed to smoke from wildfires, their lengths of stay at hospitals were longer, while the likelihood of being admitted into an intensive care unit increased. 

This increase in vulnerability is partly due to pre-existing health conditions which place the elderly at a higher risk of respiratory and cardiovascular issues exacerbated by smoke. These findings highlight the necessity of immediate action through targeted public health measures for the protection of older adults against emerging risks from wildfire smoke.⁸

Medical treatments for nasal congestion

Medical professionals diagnose nasal congestion by a history of symptoms and physical examination of the nose, ears, and throat. Tests on the throat cultures, CT scans, and nasal endoscopy may also be conducted to rule out other conditions. Treatment modalities vary according to the cause: allergic or non-allergic rhinitis.¹

Nonallergic rhinitis may be treated with saline sprays or rinses, antihistamines, corticosteroid nasal sprays, and ipratropium bromide sprays. Antihistamines, corticosteroids and decongestant nasal sprays are used only for short-term use, and anticholinergic nasal sprays may serve in the management of allergic rhinitis.¹

Effective management depends on identifying and avoiding triggers when possible, combined with appropriate medications to control symptoms. It is also important to note that some treatments, such as decongestant nasal sprays, should only be used for three days or less to avoid worsening nasal congestion. Always consult with a healthcare professional for proper diagnosis and treatment.¹

Summary

Evidence points to a strong association between smoke exposure from tobacco, wildfires, air pollution, and e-cigarettes and nasal congestion. The mechanisms in the pathophysiology of smoke include nasal passage irritation leading to inflammation, increased mucus production, and impairment of cilia that may result in chronic congestion, sinusitis, and other respiratory complications. 

Therefore, it is very important to minimise smoke exposure, especially in children and the elderly, to avoid these complications. Public health efforts to reduce smoking, improve air quality, and protect the population from wildfire smoke are paramount. Those who already suffer from nasal congestion may find avoiding their triggers and using appropriate medical treatments effective in alleviating their symptoms. However, prevention is always better. 

By being cognizant of the potential dangers of smoke exposure and taking measures to minimise them, one can dramatically improve respiratory health and overall quality of life for individuals and communities.