What Causes Sinus Infections

By | February 28, 2024

Everyone experiences sinus congestion from time to time. Many people have a stuffy nose and sinus pressure after flying or after being around someone who is sick.

But other times, your nose gets stuffy, your face becomes red, you have a fever, and you experience pain in one or both of your cheeks.

Those are all telltale signs of a sinus infection.
This article will explore what causes sinus infections, how they are diagnosed, and how they can be treated.

People get a sinus infection when bacteria, viruses or fungi (like cold germs) and other substances from mucus, saliva or blood (in case of bleeding from nose) get trapped in the nasal passages, leading to inflammation of the sinuses.

Sinus infections are common and can be very uncomfortable. The pain, headache, and pressure can make even simple tasks challenging.

While most cases heal without any problems after a few days, some people experience recurrent sinus infections. Let’s take a closer look at what causes sinus infections and how you can avoid them:

Viral Upper Respiratory Infections

Viral upper respiratory infections are the most common cause of sinus infections. The viruses that cause colds and flu can also infect the sinuses.

As the immune system fights off the viruses, it can also cause inflammation that leads to a sinus infection. Symptoms of a viral upper respiratory infection include:

  • Congestion – Your nose may get stuffier and more congested during a viral upper respiratory infection. This is because the mucus glands in your sinuses become inflamed, which leads to excess mucus production.
  • Headache – A sinus infection may lead to a headache that worsens as the day goes on. This is because the infected sinuses put pressure on the nearby nerves, which leads to a headache that increases with activity.
  • Sore Throat – This is another symptom of a viral upper respiratory infection caused by the same viruses that lead to sinus infections.
  • Fatigue – This is a common symptom of a cold or flu. It happens because your immune system is fighting off the infection, which requires a lot of energy.
  • Fevers – If a sinus infection leads to a high fever, it could be a sign of bacterial infection. Viral infections rarely lead to fevers.


Allergies can lead to sinus infections in two ways. First, allergies can cause inflammation of the sinuses. Second, some people sneeze as a way to expel mucus from their sinuses. If the mucus becomes infected, it can lead to a sinus infection. Symptoms of Allergies:

  • Congestion – You might experience even more congestion than usual if you have allergies. This happens because your immune system is trying to fight off the allergens in your body, which leads to inflammation and swelling.
  • Dry Mouth – This is another symptom of sinus infections that can happen if allergies lead to sinus infections.
  • Headache – An allergy-related headache goes beyond just a dull ache. It’s usually located in the front of your head and can make it difficult to concentrate.
  • Fatigue – Allergies can also cause fatigue by draining your energy.
  • Sneezing – Sneezing is a natural way to expel mucus from your system. If you have allergies, you may sneeze more than usual, which can lead to an infected sinus.

Irritation from Dry Air

Air that’s too dry can irritate your sinuses, which can lead to sinus infections. Dryness can come from central heating and air conditioning systems that don’t have humidity control.

It can also come from a change in weather, such as during a dry winter. Symptoms of Dry Air:

Dry Mouth – This is one of the most common symptoms of dry air irritation. –

Dryness – You may notice that your skin is dry and itchy. You might also have a dry cough. – Congestion – Your nose might run and get stuffier as a result of dry air.

Bacterial Growth

Antibiotic-resistant bacteria can grow in the mucus inside your sinuses and lead to a sinus infection. Symptoms of Bacterial Growth: – Increased Pain – Pain that starts to get worse after a week is a sign of a bacterial sinus infection. –

Swelling – MRSA, a type of antibiotic-resistant bacteria, can cause swelling in the sinuses.

Headaches – If bacteria cause a headache, it’s likely to be more severe than a common sinus infection.  Change in Symptoms – If your sinus infection symptoms change, it could be a sign of other bacteria growing in your sinuses.

Misdiagnosis and age factor

If you get a sinus infection at a young age, you may be more vulnerable to getting them again later in life. It’s not clear why this happens, but it could be due to a weakened immune system during childhood.

If you’re diagnosed with a sinus infection, it’s important to know that you might get them again. It’s common to have anywhere from one to three infections per year if you have chronic sinusitis.

Strengthening your immune system

A stronger immune system can help keep sinus infections at bay by fighting off the bacteria, viruses, and fungi that cause them.

Sleep – Getting enough sleep is crucial for a healthy immune system. This is because your body releases hormones, like cortisol and melatonin, while you sleep that strengthen your immune system.

Exercise – Exercise not only helps you sleep better, but it can also improve your immune function.

Diet – Eating a diet rich in fruits and vegetables can help strengthen your immune system and keep sinus infections at bay.

Water – Drinking plenty of water each day can help clean out your system and keep bacteria from growing in your body.


Sinus infections are incredibly common, affecting millions of people every year. While they typically clear up within a week, they can be extremely painful while they last.

These infections occur when bacteria or fungi get trapped in the sinuses, which leads to an infection. While they can happen at any time, they are most common during fall and winter months when the air is dry.

By taking steps to strengthen your immune system, you can reduce your risk of getting sinus infections.

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