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Sinus Infection



Updated June 24, 2014

Sinus Infection

Sinusitis refers to inflammation of the sinus cavities, which are moist, hollow spaces in the bones of the face. If the opening from a sinus cavity becomes plugged, the flow of mucus is blocked and pressure builds up, causing pain and inflammation.

Updated June 24, 2014

What is a Sinus Infection?

Sinus infections, also called sinusitis, are defined as inflammation of one or more sinuses. Sinuses are hollow cavities within the bones of the face. The sinuses are lined by mucous membranes that normally produce fluid – this fluid usually drains into the nasal passages and is swallowed throughout the day. However, when the drainage sites for the sinuses are blocked, the sinuses cannot drain, and an infection may develop.

The actual infection of the sinuses is most frequently caused by a viral infection (such as the common cold), but can also be bacterial in nature (and therefore responds to antibiotics). Some sinus infections are due to fungus and mold in the sinuses.

Sinus infections can be divided into different categories, the first based on how long the infection has been going on:

Acute sinusitis: Infection present for less than four weeks, and include “classic” symptoms of facial pain or pressure over the involved sinus, colored nasal discharge (green, yellow, milky or gray), nasal congestion, headache, fever, post-nasal drip and cough.

Subacute sinusitis: Infection present for more than four but less than eight weeks. Symptoms may be less severe and only include nasal congestion or post-nasal drip.

Chronic sinusitis: Infection present for eight weeks or more, and similar to that of subacute sinusitis, symptoms may be mild and consist of nasal congestion, post-nasal drip, mild headaches, chronic cough and fatigue. Some people may be misdiagnosed as having allergies when, in fact, they have a chronic sinus infection.

Recurrent sinusitis: Defined as three or more sinus infections per year. These may be due to an incompletely treated chronic sinus infection, or new infections with different bacteria.

What are the Symptoms of Sinusitis?

The following symptoms tend to be more often associated with acute sinusitis (subacute and chronic forms of sinusitis may have less severe symptoms, especially pain):
  • Facial pain and pressure over the involved sinus(es)
  • Nasal congestion
  • Colored nasal discharge
  • Decrease in smell and taste sensations
  • Fever
  • Headache
  • Bad breath/bad taste
  • Fatigue
  • Cough
  • Tooth pain
  • Ear pressure/pain
  • Post nasal drip

Do Allergies Cause Sinus Infections?

There is increasing evidence to support the idea that allergies can predispose a person to developing sinus infections. Like an inflammation in the nasal passages, whether caused by an irritant, allergy or infection (such as the common cold), blockage of the drainage sites of the sinuses can lead to the development of a sinus infection. Therefore, allergic rhinitis (hay fever) can lead to sinus infections indirectly.

What Else Can Cause Recurrent Sinus Infections?

Other causes of recurrent sinus infections include structural abnormalities within the nasal passages and sinuses, such as a deviated septum (the structure that divides the nasal passage into two sides) and other bony abnormalities that may prevent the sinuses from draining. These abnormalities are usually found on computed tomography (CT or “cat” scan) of the sinuses, and are typically treated with surgery, such as septoplasty.

Problems with low immune function, referred to as immunodeficiency, can predispose people to various types of infections, including sinusitis. Typically, immune problems related to antibody formation cause sinusitis and pneumonia. Immunodeficiencies can occur as a result of a genetic problem (such as cystic fibrosis), as a result of infection (such as HIV/AIDS), as well as other diseases that affect antibody levels (such as multiple myeloma). Allergists/immunologists are uniquely qualified to evaluate and treat people with disorders of the immune system.

Other diseases can increase the chance for a person to develop sinus infections, including gastroesophageal reflux disease (GERD) and non-allergic rhinitis. Treatment of these underlying conditions may improve or decrease the episodes of sinusitis.

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