Causes:
• Nasal polyps: These tissue growths can block the nasal passages or sinuses.
• Deviated nasal septum: A crooked septum — the wall between the nostrils — may restrict or block sinus passages, making the symptoms of sinusitis worse.
• Other medical conditions: The complications of conditions such as cystic fibrosis, HIV and other immune system-related diseases can lead to nasal blockage.
• Respiratory tract infections: Infections in your respiratory tract — most commonly colds — can inflame and thicken your sinus membranes and block mucus drainage. These infections can be viral, bacterial or fungal.
• Allergies such as hay fever: Inflammation that occurs with allergies can block your sinuses.
Risk factors:
• A deviated septum
• Nasal polyps
• Asthma
• Aspirin sensitivity
• A dental infection
• An immune system disorder such as HIV/AIDS or cystic fibrosis
• Hay fever or another allergic condition
• Regular exposure to pollutants such as cigarette smoke
Complications:
• Vision problems: If your sinus infection spreads to your eye socket, it can cause reduced vision or possibly blindness that can be permanent.
• Infections: Uncommonly, people with chronic sinusitis may develop inflammation of the membranes and fluid surrounding the brain and spinal cord (meningitis), an infection in the bones, or a serious skin infection.
Courtesy: Mayo Clinic
