Sofie Wise

Jillian Stenzel

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About Author — A Nevada-bred traveler & food nerd who dances & eats spinach, sometimes simultaneously. She writes from wherever her curiosity demands, and is passionate about spreading the wisdom of better health.

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Sinus Infection Causes

Do you have facial pain, congestion, or a runny nose that won’t go away? Or perhaps a cold that seems to have gotten worse? These are all signs of a possible sinus infection. Sinus infections are usually viral, developing just after a cold or upper respiratory infection. In most cases, sinus infections are not contagious, so it isn’t likely that you got it from someone else. Sinus infection causes range depending on what kind of infection you have.

Cold or Flu

A proceeding cold or flu are the most common causes of sinus infections. While sinus infections themselves are not contagious, the viruses causing them (usually cold or influenza) are contagious. For example, you and a family member could both have the same flu or cold, but only one of you ends up with a sinus infection afterwards. This is typically due to personal health, immune function and environmental factors.


A bacterial sinus infection may still develop after a virus such as the flu or cold. While you’re sick, your sinuses become blocked and therefore are unable to drain mucus. Mucus trapped in a warm, moist environment lays the breeding ground for harmful bacteria to develop and multiply, ultimately leading to a bacterial infection of the sinuses.

Allergens & Pollutants

Allergies can lead to sinus infections as they cause swelling in the sinus cavities and nasal passageways which prevents mucus from draining, again creating that hospitable environment for bacteria to flourish.

It’s important to note that allergies and sinus infections are two separate conditions, but often get confused for one another due to the similarity of their symptoms (i.e., facial pain, headache, pressure behind the eyes, runny nose, congestion, etc.). If you are experiencing the onset of sinus infection symptoms, but didn’t just have a cold or case of the flu, then you may actually just have allergies.

Addressing your allergies is of particular importance if you want your sinus infection to clear up, as this will remove some inflammation from your sinuses and allow for proper drainage.

Exposure to air pollution and other pollutants is also a risk factor for sinus infections due to the inflammation that chemical irritants cause in the nasal passages.


Fungi or mold

In rare cases, fungi or mold can infect the sinuses as well. This is most common among people with compromised immune systems due to HIV/AIDS, diabetes, or other autoimmune disorders. Natural disasters may also prompt the dispersal of mold spores into the air and lead to sinus infections for affected individuals in the area.

Weakened immune system

Sinus infections develop in some people but not in others, depending on health and environmental factors. A cold in a healthy individual will not usually turn into a sinus infection if proper care is taken. Having one sinus infection isn’t much of an issue, but recurring sinus infections (happening 2-4 times a year or more) are most likely a sign of having a compromised immune system.

If you think you have a weakened immune system, this could caused by lack of sleep, poor dietary choices, stress, or repeated rounds of antibiotics. You might try some natural remedies for sinus infections before taking antibiotics, or add more immune-boosting foods to your regular diet, such as garlic and ginger.

If you suffer from recurring infections and don’t think you have a weakened immune system, the cause may be related to anatomical anomalies.

Anatomical abnormalities  

Nasal polyps are small, benign growths that can develop on the nasal passages and sinus cavities due to chronic inflammation, allergies, asthma or infection. Since these growths are painless, most people do not even realize they have them. One indicator that you might have nasal polyps is if you suffer from chronic or recurring sinus infections. Nasal polyps obstruct airflow and interfere with mucus drainage which can lead to a sinus infection.

A deviated septum is another abnormality that may be causing your sinus infections. The bones and cartilage between your nose are crooked or off-center with a deviated symptom, causing breathing problems. This leads to obstructed airflow and drainage interference. If you have chronic or recurring sinus infections caused by having a deviated septum, you may want to consider a surgical procedure known as septoplasty.

A septoplasty is a very low risk, outpatient procedure. Most people breathe normally again shortly after the procedure, though cartilage and tissues can take a year to recover entirely.

If you’re suffering from sinus infection symptoms that aren’t going away, it’s a good idea to get in touch with your doctor. PlushCare is an online telehealth platform connecting patients to world class doctors online or by phone, 24/7. Easily schedule an appointment online or call (800) 221-5140. A doctor will create a treatment plan for you and have any antibiotics and/or necessary medication electronically sent to the pharmacy of your choice.

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