There are four pairs of air-filled spaces called sinuses in the human skull. An infection of the sinuses is called sinusitis. Sinusitis is considered to be acute when it is short term, and chronic when it lasts for more than eight weeks. Chronic sinusitis results from chronic inflammation and swelling of the sinus lining, causing a block in the opening of the sinuses. The mucus will not drain and stagnates. This inflammation can occur due to bacteria, fungi, viruses, allergies or abnormalities in the nasal passages.
Recurrent Acute Sinusitis
If you have frequent attacks of acute sinusitis, you may be more prone to chronic sinusitis, according to the National Institute of Allergy and Infectious Diseases. In addition, if the acute sinusitis is not treated, it can further damage the mucous membranes of the sinuses and lead to chronic sinusitis.
Fungal Causes
Studies implicate fungus as a cause for chronic sinusitis. According to researchers at the Mayo Clinic, the cause of most chronic sinus infections is an immune system response to fungus. Fungal infections should always be suspected in people with sinusitis who have their immune systems weakened from AIDS, diabetes and leukemia.
Allergies and Asthma
Sinusitis can be due to an allergic response. The most common allergies involve food, pollen and pet dander. Allergies result in chronic swelling of the sinus lining, blocking the sinuses. People with chronic sinusitis may also have an allergy to fungal organisms. According to Mayo Clinic, if you are suffering from asthma, you are at a risk for chronic sinusitis. On the other hand, about one in five patients with chronic sinusitis has asthma.
Deviated Septum
The septum is the wall or central partition between your nasal passages. A septum that is bent to one side (deviated) can block the sinus passages. As per University Of Maryland Medical Center, this structural abnormality with your nose can increase the risk of chronic sinusitis.
Polyps
Polyps are grape-like swellings, which develop in the sinuses. These can block the sinus openings and mucus drainage, often resulting in chronic sinusitis.
Environmental Pollutants
Pollutants in the air, fumes, dust, and smoke can affect the function of the sinuses and cause sinusitis.
Associated Diseases
In patients with HIV/AIDS, the mucous membranes do not function properly and often are not able to resist infections. In conditions like cystic fibrosis, there are abnormalities in the mucous. The mucus becomes thick and stagnant, resulting in chronic sinusitis.
