Nasal inflammation, medically termed rhinitis, is a common condition affecting the lining of the nose. It involves swelling and irritation of the nasal passages, often leading to congestion, a runny nose, sneezing, and itching. While often temporary, rhinitis can become persistent. A variety of factors contribute to its development.
Allergic Reactions
Allergic rhinitis arises when the body’s immune system overreacts to otherwise harmless substances in the environment, known as allergens. Common allergens include pollen, dust mites, pet dander, and mold spores. Upon exposure, the immune system of a sensitized individual produces specific antibodies, primarily immunoglobulin E (IgE), which attach to mast cells in the nasal lining.
When IgE-coated mast cells encounter the allergen again, they release inflammatory chemicals, most notably histamine. Histamine causes blood vessels in the nose to dilate and become more permeable, leading to swelling and increased mucus production. It also stimulates nerve endings, resulting in itching and sneezing. This immune response produces uncomfortable nasal inflammation.
Environmental Irritants
Nasal inflammation can also result from direct exposure to environmental irritants. Tobacco smoke, including secondhand smoke, and air pollution (particulate matter and gases) directly inflame the nasal lining.
Strong chemical fumes from cleaning products, perfumes, or industrial chemicals can trigger an inflammatory reaction in the sensitive nasal mucosa. General dust can also act as a physical irritant. Additionally, sudden changes in temperature or humidity can cause the nasal passages to swell and produce excess mucus, leading to symptoms of rhinitis.
Infections
Microorganisms frequently cause nasal inflammation, with viral infections being the most common. Viruses, such as those responsible for the common cold and influenza, infect the lining of the nose and throat. The body’s immune response to these pathogens causes inflammation, leading to increased mucus production, sneezing, and nasal congestion.
Bacterial infections can also contribute to or complicate nasal inflammation, particularly in cases of bacterial sinusitis, which may develop after a viral infection. When sinus openings become blocked by inflammation, mucus can accumulate, creating an environment conducive to bacterial growth. Fungal infections can also lead to inflammation within the nasal passages.
Structural Issues
Physical abnormalities or obstructions within the nasal passages can cause or worsen nasal inflammation by impeding airflow and drainage. A deviated septum, where the thin wall separating the nostrils is off-center, can restrict nasal airways, leading to chronic congestion and inflammation. This misalignment can disrupt normal mucus flow and make the nasal passages more susceptible to irritation.
Nasal polyps, which are non-cancerous, soft growths on the lining of the nose or sinuses, can block the nasal passages and sinus openings. Their presence can lead to persistent inflammation, congestion, and a reduced sense of smell. Enlarged turbinates, structures inside the nose that help filter and humidify air, can also swell, further obstructing airflow and contributing to chronic nasal inflammation.
Systemic Conditions
Nasal inflammation can stem from broader health conditions or internal factors affecting the entire body. Hormonal fluctuations, such as during pregnancy or with thyroid dysfunction, can influence nasal blood flow, leading to swelling and congestion. Certain medications, including those for blood pressure, may have side effects that include nasal inflammation.
Gastroesophageal reflux disease (GERD) can also contribute to nasal inflammation, possibly due to stomach acid irritating the upper airway. Systemic diseases, such as certain autoimmune conditions, can manifest with chronic nasal inflammation. These internal factors can disrupt the normal function of the nasal lining, making it prone to irritation and swelling.