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Southwestern United States
Information for patients with allergy and related problems
in the Southwest

Causes of allergies and sinusitis: rhinitis, sinusitis, mechanisms of respiratory allergy


The words "SINUS" and "ALLERGIES" do not mean the same thing!

What are sinuses?  These are air-filled cavities in the bones of the face below and between the eye sockets and above the bridge of the nose. The sinuses are in the bones that are part of the walls of the nasal cavity but are not part of the nasal cavity, and they are not in the respiratory air stream. The sinus cavities communicate with the nasal cavities by tiny holes. When these holes become blocked by conditions that inflame the lining of the nose such as allergy or virus infection, fluid can accumulate in the sinuses.

What causes sinusitis?  Any cause of inflammation in the sinuses may cause sinusitis.  The most common cause of acute sinusitis is a virus infection such as the common cold, during which fluid accumulates in the sinus cavities.  Allergic rhinitis may also cause fluid accumulation. When bacteria (germs) breed in this abnormal fluid accumulation, bacterial sinusitis follows.  

Acute sinusitis
lasts up to 2 weeks. Occasional attacks of acute sinusitis usually follow a cold or influenza.  Frequent attacks of acute sinusitis (3 or more/year) are often caused by allergic rhinitis (nasal allergy).  Uncomplicated acute sinusitis rarely needs antibiotic treatment.

Chronic sinusitis
is usually a bacterial and/or fungal infection that persists for months or years.  Less common causes are structural abnormalities in the nasal cavities, aspirin sensitivity, immune deficiency disease, and cystic fibrosis, all of which tend to cause chronic sinus disease. Contributory causes are heavy exposure to people with colds or influenza, or exposure to tobacco smoke.  

Contrary to some reports, the vast majority of cases of acute sinusitis are not caused by fungi (molds).  However, some patients with chronic sinusitis have persistent fungal infection, often with an abnormal immune reaction to the fungus in the sinuses (allergic fungal sinusitis).

Symptoms of sinusitis. These include pain or pressure in the face or around the eyes (worse on bending forward), a yellow or green nasal discharge and nasal stuffiness. There may be fever, diffuse headache, increased mucus drainage in the throat and loss of smell. Nasal stuffiness and/or headache without other symptoms are usually not caused by acute sinusitis, and more often are from allergic rhinitis.  Acute sinusitis commonly resolves without antibiotic treatment. Persistent sinusitis usually requires medical treatment with antibiotics, often supplemented with anti-inflammatory and decongestant medications and nasal irrigation.  Chronic sinus disease may require surgery.  Treatment of seasonal allergic rhinitis by an allergist may help to prevent attacks of sinusitis that commonly complicate this condition when it is severe.

Further Reading:
AAAAI: Sinusitis

Additional links

Disclaimer:   This site is for educational purposes only.  Any information that you have found in this web site is not intended to replace medical care or advice given to you by your own physicians. You should consider consulting your local medical library and other web sites for additional information. 

Comments and suggestions welcome!   Email:
Content Owner:  Michael J. Schumacher, MB, FRACP, The University of Arizona

Updated 5/2012