What are the causes and symptoms of sinusitis?
Sinusitis is almost always due to an infection, although swelling from allergies can mimic the symptoms of pressure, pain, and congestion; and allergies can set the stage for a bacterial infection. Bacteria are the most common cause of sinus infection. Streptococcus pneumoniae causes about 33% of all cases, while Haemophilus influenzae causes about 25% of all cases. Sinusitis in children may be caused by Moraxella catarrhalis (20%). In people with weakened immune systems (including patients with diabetes; acquired immunodeficiency syndrome or AIDS; and patients who are taking medications which lower their immune resistance, such as cancer and transplant patients), sinusitis may be caused by fungi such as Aspergillus, Candida, or Mucorales. Acute sinusitis usually follows some type of upper respiratory tract infection or cold. Instead of ending, the cold seems to linger on, with constant or even worsening congestion. Drainage from the nose often changes from a clear color to a thicker,
