The paranasal sinuses swell, i.e. becoming larger and unusually rounded. However, what does cause this expansion?

There are a number of factors responsible for swollen sinuses. Such as,

The sinuses feature mucous membranes that continue into the nasal passage. Since the sinuses reside within the bones, they are inflexible. The healthy sinuses maintain pressure equalization, an even distribution of the pressure. However, the nasal membranes swell in the wake of respiratory disorders, blocking the slim air channels opening into the sinuses and affecting the pressure distribution. If the pressure outside the sinuses is more than that within the sinuses, the sinus mucosa may swell and release fluids, compressing and reducing the air volume.

Both bacterial and viral infections may cause swelling of the sinuses. The respiratory infections stimulate growth of microorganisms that may venture into the sinuses and cause swelling of the mucous membranes.  The bacteria, fungi and / or virus occupying the sinuses illegally irritate the mucosa, causing swelling of the sinuses.

The cheek and nose trauma can fracture the maxillary and ethmoid sinuses. Some times sinus infection may break the membranes, causing bleeding. The injuries to the membranes of the paranasal sinuses also lead to swollen sinuses.

In some people, allergies lead to swelling of the sinus openings (ostia). Airborne or environmental allergens and mold may initiate swelling of the sinuses. Alcohol may exacerbate the swelling.

Sinus swelling is one of the main symptoms of sinusitis. However, many other diseases also increase the size of the sinuses and change the shape. Here is a short list of the disease:

Asthma

Autoimmune disorders

Cocaine abuse

Dental problems

Eustachian tube dysfunction

Fracture of the nasal bone

Juvenile nasal angiofibroma (JNA) (a benign growth of the upper throat or the rear part of the nose)

Rhinophyma (bulbous ruddy nose)…

Some activities, such as scuba diving, swell the sinus due to increase in pressure underwater. If you swim in contaminated pool, the water may enter your sinuses, causing sinus infection and swelling.

Anatomical problems such as tumors, nasal polyps and / or deviated septum may block the sinus cavities, causing swelling.