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Column originally published Sep 28, 2010

Allergy And Virus infection Can Cause Sinusitis

Question: Several weeks ago, our daughter was very sick. She had high fever, and shortly afterwards developed a bad rash on her face, around her eyes, her nose, and her mouth. She was admitted to the hospital. After some tests, we were told that our daughter had a Staph infection. She was treated with IV antibiotics for several days, and she got better slowly. The paediatrician told us that the infection started from her sinuses. This had never crossed our mind. Our daughter has a stuffy nose all the time, and she snores at night. We never thought it was something serious until now. Please tell us how we can prevent this from happening again.


You are not alone in not able to recognize your daughterʼs illness. Sinus infection, also called sinusitis, is actually very common. Many people think that they just have a bad cold, or that they have sinus headache or sinus congestion, without recognizing that these can be signs of sinus infection.

The two most common causes of sinusitis are virus infection and allergy, and sometimes these two can work together to produce severe sinusitis.

When we get a virus infection in the nose, the mucosa that covers the inside of our nose becomes swollen, giving rise to the feeling of stuffiness inside. The mucus glands in the mucosa produce a large amount of mucus, which can drain forward out of the nose, or drain backwards into the throat. The swelling of the mucosa as well as the mucus can block the tiny openings of the sinuses.

If the virus infection is mild, the mucosal swelling will start to improve after several days. The mucus production will decrease at the same time, although the mucus can become a little thicker towards the end of the virus infection. However, if it is a more serious virus infection, the mucosal swelling can last much longer. When this happens, the sinuses will be blocked for a longer time, and mucus will accumulate inside the sinuses.

This is the perfect environment for bacteria to grow inside the sinuses and produce sinus infection. There are many normal bacteria that live inside our nose, on the surface of the mucus membrane. These bacteria wonʼt cause any problem when the mucus membrane is healthy. However, when the sinuses are clogged up with mucus, these same bacteria can grow and multiply to produce sinus infection.

You may have heard of bacteria called Strep and Staph. These are shortened names of common bacteria that can cause sinus infection. Some of them can produce a poison which was responsible for your daughterʼs severe rash. Fortunately, your doctor was able to recognize the seriousness of her illness and gave her the proper antibiotics intravenously.

Allergies in the nose can also cause sinus infection, although the mechanism is slightly different. The most common triggers of these allergies are dust, molds, as well as pollens. Pet danders from cats and dogs can cause similar problem for those who are allergic to these animals.

When exposed to one or more of these triggers, a person who has nasal allergy will develop swelling of the mucosa inside the nose. In addition to increased production of mucus, these individuals also experience itchiness in the nose and throat, as well as sneezing. The end result is almost the same as having a virus infection: the sinuses can get clogged up and filled with mucus.

Depends on what a person is allergic to, the symptoms can be seasonal if a specific pollen is the culprit. However, the problem can also be more prolonged and even year-round, if the allergy is towards dust and moulds, or to pets. These individuals can have stuffy nose and blocked sinuses almost continuously. As a result, they can develop low grade sinus infection, which they donʼt even recognize. The may feel unwell from time to time, sometimes with thick nasal drainage, or sinus headache. Snoring at night is very common, especially in children. Their adenoids can become swollen and partially blocking their airways.

When a person with nasal allergy gets a virus infection, the mucosa inside the nose and sinuses can become even more swollen. Essentially he gets a double whammy: the mucosal swelling and blockage of sinuses will last much longer than those without nasal allergy. As a result, the chance of developing sinusitis is much greater.

I should point out to you that sinus infection can be even more serious than what your daughter has experienced. Our sinuses are very close to the eyes as well as to the brain. Severe and sometimes unrecognized sinus infection can spread to the eyes, causing permanent damage and blindness if proper treatment is delayed. Sinusitis can also spread to the brain, with serious complications like meningitis and brain abscesses.

If your daughter has frequent nasal congestion and snoring, you should work with your doctor to find out what she may be allergic to, and try to eliminate some of the things in the home that can trigger her allergy. Some children need to use a nose spray daily to keep the allergy under control and to keep the sinuses open to prevent recurrent sinus infections. A long-acting anti-histamine can also be beneficial.