Sinus Infection

What is a Sinus Infection?

A sinus infection, also referred to as sinusitis, occurs when the tissue lining in the sinuses become inflamed or blocked. The sinuses are divided into four paired cavities and are connected by narrow passages. The role of the sinuses is to produce a thin mucus that drains through the passages to keep the nose clean and free from bacteria. However, sometimes the sinus cavities and passages can become inflamed or blocked with fluid, thereby creating a fertile environment for bacteria to grow. Once this happens, an infection can occur, which is known as bacterial sinusitis or rhinosinusitis (“rhino” meaning nose).

There are four paired sinus cavities, each located in different places in the head near the nose and eyes. The cavities are named after the bones that give them their structure.

  • Ethmoidal sinuses are located between the eyes
  • Maxillary sinuses are located below the eyes
  • Sphenoidal sinuses are located behind the eyes
  • Frontal sinuses are located above the eyes

There are four different types of sinusitis. The types include:

  • Acute bacterial sinusitis. A sudden onset of cold symptoms (runny or stuffy nose, fever, facial pain) that do not go away after 10 days or gets better only to get worse again (“double-sickening”). This type of sinusitis responds well to antibiotics and decongestants.
  • Chronic sinusitis. Defined by nasal congestion and drainage, facial pain and pressure, and a reduced sense of smell for at least 12 weeks.
  • Subacute sinusitis. This term is used when the sinus infection lasts 4-12 weeks.
  • Recurrent acute sinusitis. This term is used when the sinus infection occurs at least four times a year and lasts less than 2 weeks each time.


A sinus infection (sinusitis) can be difficult to distinguish from a common cold or allergies. Often, it is the duration of symptoms that signals a sinus infection. The most common symptoms of sinusitis include:

  • Post-nasal drip (mucus draining down the back of the throat)
  • Nasal discharge or congestion (discharge can be thick, tacky, green or yellow)
  • Facial pressure in or near sinus cavities, headache, pain in ears or teeth
  • Bad breath (Halitosis)
  • Cough
  • Fever
  • Fatigue


There are many causes for sinusitis, and they can differ between adults and children. Sinus infections are generally triggered by bacteria, a virus, or fungus that creates inflammation and blockage in the sinus canals. More specifically, the most common causes for sinusitis include:

  • A common cold can trigger sinusitis
  • Allergies can develop into sinusitis
  • Polyps (growths) inside the nose and sinuses
  • Deviated septum (causes the nasal canal to be narrower on one side, increasing the risk for blockages)
  • A weakened immune system from illness or medications
  • Smoking increases your risk for sinusitis, and is harmful to those around you

Infants and young children are exposed to more bacteria and viruses at day care, and further increase their risk of sinusitis by using pacifiers and drinking from a bottle while laying down. 


Sinus infections are often triggered by a common cold or allergies. It makes sense that the best forms of prevention are good hand hygiene and being especially mindful during cold and flu season to avoid others who are sick. It is also helpful to strengthen your immune system by getting proper rest, adequate nutrients, and staying hydrated. Nasal rinses and nasal sprays can also help to reduce the risk of developing a sinus infection.

 Additionally, allergies can trigger sinusitis. It is an important preventative measure to manage your allergies well. This may include taking allergy medications or visiting an allergy doctor to decide the best course of action.

Smoking is another risk factor for developing sinusitis. Smoking not only irritates the sinuses, but it also damages the protective barriers in the nose and respiratory system that can help prevent sinus infections. Talk with your doctor if you are wanting help with quitting smoking.


Sinus infections can usually be treated without doctor intervention. However, some cases may require a trip to the doctor. If your symptoms have lasted less than 10 days and haven’t gotten worse, it is probably a viral infection. If your symptoms have lasted longer than 10 days and have gotten worse, you may have a bacterial infection and it is important to contact your primary care provider.

To diagnose sinusitis, your doctor will use an endoscope to look inside your nose, ears, and throat. Once your doctor has determined sinusitis, it may be recommended that you take medications to help with pain and decongestion, as well as trying a nasal rinse or nasal spray. If your doctor believes that it is a bacterial infection, he or she may prescribe an antibiotic. On some occasions, more typical with chronic sinusitis, you may be referred to an ENT (ear, nose, and throat specialist).


There are many forms of treatment for sinusitis. The treatment is dependent upon the type of sinus infection and duration of symptoms. Common treatments for sinusitis include using OTC medications for pain and decongestion, nasal rinses and nasal sprays, and sometimes antibiotics.

Simple viral sinus infection

  • OTC medications such as acetaminophen for pain, ibuprofen for inflammation, and decongestants
  • Allergy medications
  • Nasal rinses (nasal irrigation) and nasal sprays
  • Drinking plenty of fluids

If symptoms do not resolve or improve in 10 days, your healthcare provider may prescribe the following:

  • Antibiotic
  • Oral or topical decongestants
  • Prescription intranasal steroid sprays (do not use non-prescription nasal sprays for longer than 3 days to 5 days, as it may increase congestion)

Chronic sinusitis

This type of sinusitis is long-term, and treatment generally focuses on targeting the underlying cause. Typically, the underlying cause for chronic sinusitis is allergies. Treatment will focus on managing your allergies. Treatments typically include:

  • Intranasal steroid sprays
  • Topical antihistamine or oral pills
  • Nasal rinse that includes saline solution or other medication
  • Leukotriene antagonists to reduce swelling and allergy symptoms

If none of the above treatments help with symptom relief or recovery, a CT scan will be ordered to determine whether there are structural issues in the nose and sinuses. The scan will help your doctor decide if surgery is needed to correct any structural issues, remove polyps, or address fungal infections.


Although rare, if left untreated, sinus infections have the potential to become life-threatening. A person can develop meningitis, which is an infection of the membranes that encase the brain and spinal cord. Meningitis can be life-threating. Left untreated, sinusitis can develop into infections of the brain, eyes, or nearby bones. It is important to consult with your doctor if symptoms of sinusitis have gotten worse or not cleared up after 10 days.

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