The nostrils are the two openings of the nasal cavity located at the bottom of the nose. They have a respiratory, immunological and olfactory function. The pathologies of the nasal cavities are of different natures: inflammations, deviations of the septum, tumors. They are diagnosed by an ENT, often during a simple clinical examination. Treatment of rhinitis is often symptomatic. Surgical intervention is necessary to treat certain pathologies (deviations, tumors, foreign bodies). 

The nostrils are the two openings of the nasal cavity located at the bottom of the nose. The nasal passages are air passages carved into the bones of the face that make up the nasal cavity, the upper part of the respiratory system. They are separated by a vertical septum with the cartilaginous and bony skeleton, the nasal septum. They have a posterior part (behind) which opens through two funnel-shaped openings (the choannes) in the pharynx. And their anterior part (in front) opens to the outside through the nostrils.

The nostrils, integral parts of the nasal cavities, have a triple function:

Respiratory function

The air entering through the nostrils is filtered, moistened (thanks to the mucus composed of 95% water that covers the inside of the nasal cavities) and warmed in the nasal cavities before reaching the trachea and bronchi.

Immunological function

If the air that enters through the nostrils is made up of microbes, the nasal passages can prevent their spread to the inner ear and bronchi via:

• Epithelial defense: the nasal cavity is lined with a mucous membrane rich in blood vessels. Mucosal cells have tiny cilia on their surface, and they produce mucus that traps inhaled impurities. The latter are then evacuated by the eyelashes towards the anterior part of the nose or towards the throat, and eliminated from the respiratory tract;
• An immune system annexed to the nasal mucosa: immunoglobulins present in nasal secretions, secretory IgA, inhibit bacterial adhesion to the surface of the mucosa, neutralize viruses and toxins, and prevent the absorption of antigens;
• Inflammation, the body’s physiological defense and adaptation response to its environment.

Olfactory function

The air that enters the nostrils comes in contact with olfactory receptors which are located in the upper part of the nasal cavity. These receptors are special nerve cells that are sensitive to different chemicals. After stimulation, they produce a nerve impulse which is sent to the brain which perceives it as an odor.

Pathologies and abnormalities of the nasal cavities are treated by an otorhinolaryngology (ENT). They are of different kinds.

Inflammation

Called rhinitis, inflammation of the nasal cavities is most often of infectious origin (common cold) or allergic (pollen, animal hair, mites, etc.). It is characterized by acute or chronic localized inflammation of the nasal mucosa. Symptoms of rhinitis include a runny nose, sneezing, and a blocked nose. It is likely to spread to the sinuses (sinusitis).

There are other rarer forms of rhinitis:

• Atrophic rhinitis is a form of chronic rhinitis in which the lining becomes thinner and sclerotic. The nasal passages dilate and dry out. Scabs form inside the nose, accompanied by a bad smell. People may have repeated bleeding and lose their sense of smell (anosmia). Atrophic rhinitis mainly affects the elderly or those who have had sinus surgery;
• Vasomotor rhinitis is a form of chronic rhinitis in which the usual symptoms of allergy are seen in the absence of allergy. Symptoms are aggravated by dry air.

Partition deviations

The nasal septum is often the site of deviations which give it, from the front, a more or less elongated appearance. These deviations can be of congenital origin or following a trauma. Deviated septum is a cause of chronic rhinitis and nasal obstruction.

Foreign bodies

Foreign bodies introduced through the nostrils can cause obstruction and infection.

Tumors

• Benign tumors: polyps, translucent gelatinous masses, can block the nasal passages. This leads to loss of smell and frequent infections.
• Malignant tumors: These change the bone structure of the nasal cavity, causing pain, obstruction, and discharge of serous fluid or blood.

Other pathologies

• Nasal tuberculosis
• Nasal syphilis

Acute rhinitis, of viral origin, can be treated with:

• Nasal spray or oral decongestants;
• Antihistamines to control a runny nose.

Chronic rhinitis can be treated with:

• Decongestants to relieve symptoms;
• In the case of atrophic rhinitis, ointment antibiotics applied in the nose can destroy the bacteria. Nasal spray or oral estrogen, or oral vitamins A and D, can reduce scab formation;
• In case of vasomotor rhinitis, the treatment is symptomatic. A humidified central heating system or a vaporizer to increase humidity may be beneficial, and corticosteroids and antihistamines in nasal spray are sometimes helpful.

Surgical interventions are performed in the following cases:

• To replace the nasal septum in the correct position and restore the correct shape to the nose. The intervention is carried out only in adulthood, at the end of growth;
• To remove a foreign body;
• To remove tumors. When the tumors are malignant, surgical removal is coupled with radiotherapy.

Most pathologies and abnormalities of the nasal cavity are diagnosed clinically on the basis of an examination, but additional examinations may be necessary.

• In case of nasal obstruction, nasal endoscopy may be performed to explore the nasal cavities and sinuses to diagnose architectural or mucosal abnormalities;
• The extent of nasal obstruction can be assessed by measuring nasal resistance with rhinomametry (an examination that involves placing two pressure sensors, one in the obstructed cavity and the other in the unobstructed cavity, to measure the air pressure entering and leaving a cavity);
• In the case of chronic rhinitis with persistent symptoms, a biopsy may be taken to rule out cancer;
• Skin tests can determine the allergic nature of rhinitis.