Causes of sinusitis

Any condition or exposure that causes inflammation in the nasal cavity or the opening to the sinuses can start the cycle of sinusitis. Inflammation may be incited by anatomic deformities, allergies, infections, problems with the immune system, environmental factors or dietary factors.

Nasal polyps

may protrude into the nasal cavity blocking the airway and not allow mucus to drain properly.

Enlarged Turbinates

Turbinate hypertrophy (enlarged turbinates) is usually caused by allergies, sinus inflammation or environmental irritants. However, when the middle turbinate enlarges with air (concha bullosa) it blocks the sinus opening creating a build-up of mucus which can become infected.

Deviated Nasal Septum

Your nasal septum is made up of bone and cartilage and separates the nasal cavities. While the septum is usually straight and symmetrical – a deviated septum happens when the cartilage leans left or right. This can cause obstructions to the nasal passages and blockage. This is a very common condition and affects most individuals, though the severity differs among individuals.

Facial Trauma

A trauma to the frontal or maxillary sinus can result from either a fall or force applied to the face. This can lead to swelling or damage to the bones of the sinus cavities causing problems with drainage.

Nasal Allergies

Allergy symptoms such as your nose or eyes itching, watery eyes, runny nose – may lead to swelling in the nasal cavities – causing your sinusitis.

Autoimmune diseases

certain conditions or disease may predispose individuals to sinusitis, such as those who are immunocompromised, have cystic fibrosis, diabetes or HIV.

Environmental irritants

such as cigarette smoke can make the sinus tissues swell. Immune deficiencies

Overuse of Decongestants

While decongestants help shrink the inflamed sinus tissues, it should only be used under a doctor’s direction as overuse of some medications such as Afrin can cause a ‘rebound effect’ and lead to a condition called ‘rhinitis medicamentosa’.

Viral

Most cases of sinusitis are caused by viral infections such as a cold, and usually resolve on their own over the course of about 10 days

Bacterial

Usually occurs after the sinus cavities are blocked and can be caused by streptococcus pneumonia, haemophilus influenza and Moraxella catarrhalis; such as bacterial infections of the upper respiratory tract

Fungal

Generally rare and can occurs after an injury to the sinuses

Upper Respiratory tract infections

Include infections of the larynx pharynx and nasal cavities. Sinusitis can results from infections of these other sites as they are next to and are a part of the upper respiratory tract.