The most common direct
cause of acute sinusitis is bacteria. The role of bacteria or other
infectious agents is complicated in chronic sinusitis. They may
play a direct, an indirect, or, in some patients, infectious agents
may not play any role at all.
Sinusitis is most often
an acute condition, which is self-limiting and treatable. In some
cases, the inflammation in the sinuses persists or is chronic.
A flu or cold virus
could lead to acute sinusitis. Viruses themselves do not usually
cause sinusitis directly. They create conditions for bacterial growth,
by causing inflammation and congestion in the nasal passages (called
rhinitis) that leads to obstruction in the sinuses. Rhinitis is
the precursor to sinusitis in so many cases that many now refer
to most cases of sinusitis as rhinosinusitis.
the following sinuses:
- The maxillary sinuses (behind
the cheekbones) are the most common sites.
- The ethmoid sinuses (between
the eyes) are the second most common sites affected by colds.
- The frontal sinuses (behind the
- The sphenoid sinuses (behind
Though colds cause
inflamed sinuses, less than 5% of people with colds develop true
Fungal infections can
be very serious, and both chronic and acute fungal sinusitis require
immediate treatment. Fungal ball is not invasive and is nearly always
Fungal infections should
be suspected in people with sinusitis who also have diabetes, leukemia,
AIDS, or other conditions that impair the immune system. Fungal
infections can also occur in patients with healthy immune systems
but they are far less common.
Viral Sinusitis. Viruses
are directly implicated in only about 10% of sinusitis cases.