1. Health
You can opt-out at any time. Please refer to our privacy policy for contact information.

Causes of Sinusitis: Allergies


Updated January 04, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

The inflammation and congestion caused by allergies, especially if untreated, can cause sinusitis. The sinuses are hollow recesses in your skull. They are lined with mucous membranes. The mucous inside of the sinus cavities usually drains into the nasal passageways and subsequently out of the nose or into the back of the throat. When the mucous membranes become inflamed they may swell, making it difficult for them to drain. Excess mucous or mucous that is too thick may contribute to the problem and the sinuses may become clogged causing pressure and pain. The inability of the sinuses to drain and the lack of airflow create an environment which is ideal for bacterial growth. This is how allergies can lead to a sinus infection.

Acute Sinusitis

Acute sinusitis is sinusitis that lasts for 4 weeks or less. Most cases of acute sinusitis start out with a common cold but could be caused by allergies as well.

Chronic Sinusitis

Chronic sinusitis lasts much longer than acute sinusitis, 3 months or more. People often misdiagnose themselves with allergies when they are actually suffering from chronic sinusitis. According to a study by the Asthma and Allergy Foundation 51% of people participating in the study had misdiagnosed themselves with allergies when they actually had sinusitis. They may have originally been suffering from allergies and later developed a chronic sinus infection. Once you develop a sinus infection, allergy medications are no longer adequate to treat the condition. Treatment should involve antibiotic medications and in some cases sinus surgery.

Preventing Sinusitis When You Have Allergies

Adequate treatment of allergies is important in preventing the development of sinusitis. Avoiding allergy triggers, seeing a qualified physician, and managing congestion are key. Mild cases may be controlled using over-the-counter antihistamines. There are many different medications available including an antihistamine, Allegra, which claims not to cause drowsiness. Claritin (loratadine) and Zyrtec (cetirizine hydrochloride) are also much less sedating than older antihistamines such as Benadryl (diphenhydramine).

Over-the-counter decongestants such as pseudoephedrine or the nasal spray Afrin (oxymetazoline) may be helpful in managing congestion. However, these decongestants can cause rebound congestion, (also called nasal spray addiction), if used longer than 3 days. Some prescription decongestants claim not to cause rebound congestion or to have a lower risk.

In most cases excess mucous caused by allergies is thin, however, if you have thick mucous you should increase your fluid intake. Keeping secretions thin will help keep the sinuses draining. A cool mist humidifier can also be helpful.

A doctor called an immunologist can test you for allergies, pinpointing the allergic trigger. This is extremely helpful. An immunologist can prescribe appropriate medications for allergies and administer immunotherapy (allergy shots) to those who qualify and choose this type of treatment. Allergy symptoms that do not quickly resolve, or do not respond to over-the-counter medications need to be evaluated by a qualified physician.

Complications of Chronic Sinusitis

Untreated chronic sinusitis can damage the tissue inside of the sinuses. Abnormal growths such as nasal polyps occur frequently in patients with frequent and/or chronic sinus infections. This can result in a cycle of recurrent sinus problems as damaged and enlarged tissues make it even more difficult for the sinuses to drain properly. Of course, some people may be genetically predisposed to these problems as well.

Enlarged turbinates (concha bullosa), deviated septums and nasal polyps need to be surgically repaired by an otolaryngologist (ear, nose, throat or ENT doctor). Sinus surgery is performed using an endoscope, a long tube with a camera on the end of it which allows the surgeon to see inside of the sinuses. Sinus surgery can usually be performed in a same day surgery setting and you can go home the same day. Once the sinuses have been cleared of diseased tissue and they are able to drain properly, any infection often resolves on its own. In some cases your surgeon may prescribe you antibiotics after surgery to clear up any remaining infection.


American Academy of Allergy Asthma and Immunology. Sinusitis. Accessed: December 28, 2012 from http://www.aaaai.org/conditions-and-treatments/library/At-a-glance/sinusitis.aspx

American Academy of Otolaryngology - Head and Neck Surgery. Sinusitis. Accessed: December 28, 2012 from http://www.entnet.org/HealthInformation/Sinusitis.cfm

Pubmed Health. Sinusitis. Accessed: December 28, 2012 from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001670/

  1. About.com
  2. Health
  3. Ear, Nose, & Throat Disorders
  4. Allergies
  5. Causes of Sinusitis: Allergies

©2014 About.com. All rights reserved.

We comply with the HONcode standard
for trustworthy health
information: verify here.