Causes
Your sinuses are
hollow spaces within the bones of your face, behind and above your nose.
They humidify and warm the air you breathe, aid your sense of smell, and
improve the sound of your voice. They also make mucus, which cleans and
moisturizes your nasal passages.
Inside your
sinuses are tiny hairs, called cilia, which constantly sweep
mucus out of your sinuses and into your nose and throat. Your sinuses
drain into your nose through small openings called ostia.
When the ostia become blocked, mucus backs up in your sinuses.
When your sinuses
can't drain, microorganisms such as viruses and bacteria can multiply
and cause infection. Infection causes swelling, which makes it even
harder for your sinuses to drain.
Common causes of
sinus blockage, which can lead to chronic sinus infections, are:
-
Respiratory
tract infections.
Infections in your respiratory tract — most commonly, colds — can
inflame and thicken your sinus membranes, impeding mucus drainage
and creating conditions ripe for bacteria growth.
-
Allergy.
Your immune system may mistake harmless elements such as pollen, pet
dander or dust mites as violent attackers, and fight back. The
results of this battle mimic signs and symptoms of a cold — stuffy
nose, itchy eyes, cough — and may cause congested sinuses. Seasonal
allergies may increase your risk during distinct times of the year.
If you have allergies to dust mites or pets, your symptoms could
appear and reappear at seemingly more random times. Fungi also can
cause a specific type of chronic sinusitis called allergic fungal
sinusitis.
-
Nasal or
sinus obstructions.
Nasal polyps, small growths that resemble grapes, can obstruct the
passages from your sinuses to your nose, making proper drainage
difficult. The size and shape of the opening between your sinuses
and nasal cavity also may obstruct sinus drainage.
Other causes of
chronic sinusitis include:
-
Lack of
antibodies called immunoglobulins in your immune system
-
Cystic
fibrosis, which causes your body's secretions to become thick and
sticky in your sinuses as well as in your lungs
-
Trauma, such
as a fractured facial bone, which may obstruct one or more of your
sinus cavities
When to seek
medical advice
Typically, people
have several episodes of acute sinusitis before developing chronic
sinusitis. If you've had sinusitis a number of times and the condition
doesn't respond to treatment, or if your infection has lasted more than
3 months, ask your doctor if you might have chronic sinusitis. You may
be referred to an allergist or an ear, nose and throat specialist.
Chronic sinusitis
can increase the frequency and severity of asthmatic flare-ups in people
with asthma and in people who have asthma-like reactions to aspirin and
related medications such as ibuprofen. If you experience wheezing or
shortness of breath, or if you're concerned about possible aspirin
allergy, see your doctor for additional tests.
Screening and
diagnosis
Chronic sinusitis
can be difficult to diagnose because the symptoms may be very similar to
colds or allergies. Provide your doctor with as much detail about the
type and duration of your symptoms as possible.
Your doctor may
recommend allergy skin tests to determine whether allergies are causing
your sinusitis. Allergy skin tests are safe, involve little if any
discomfort and usually can be done in about 25 minutes.
These procedures
help in diagnosing chronic sinusitis:
-
Nasal
endoscopy.
A thin, flexible tube (endoscope) with a fiber-optic light inserted
through your nose allows your doctor to visually inspect the inside
of your sinuses.
-
Imaging.
Images taken using a computerized tomography (CT) scan can show
details of your sinuses and nasal area, including a deep
inflammation or infection that may be difficult to detect using an
endoscope.
Chronic sinusitis
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