Health & Medicine General Medicine

Sinus Infection | Causes, Symptoms & Treatment


Sinuses are air pockets within the bones of the skull and face that are connected to your nasal passages through the osteomeatal complex, which consists of small tubes or channels. Air can flow from the nose into the sinuses through these channels, and mucous can drain from each sinus into the nose.

What are sinuses?

The paranasal sinuses, or simply sinuses, are air-filled cavities around the nose in the skull bone. There are four pairs of sinuses on the left and right sides; the frontal(behind forehead), the maxillary(behind cheeks), and the ethmoidal and the sphenoidal(both behind nose). All the sinuses are individually connected to the respective side of the nose via small openings or ostia.

The sinuses are lined with mucus producing cells, like the ones found in the nose. Similar to the nose, the sinus secretions also clear the passages from allergens and pollutants. The secretions flow in flow towards the ostia into the nose. Maxillary is the most commonly infected sinus, while ethmoidal and sphenoidal sinuses are the least infected but can be life-threatening.

Infections of the sinus

When the sinus opening is blocked, it results in stasis of the secretions inside the sinus. Stasis leads to loss of cleaning function and growth of bacteria, viruses or fungi in the sinus, termed sinusitis. The blockage may be due to nasal secretions or may be mechanical. It is rare for sinusitis to occur without rhinitis or nasal inflammation. For this reason doctors now prefer the term Rhinosinusitis.

The nasal and sinus linings become red, engorged, and oozy. Most of the times, it is viral, but it can turn into a bacterial or even fungal infection if it remains blocked for longer periods.

Acute, Sub acute, recurrent , or Chronic Sinusitis:

Clinically, sinusitis is divided into acute, sub-acute, recurrent, and chronic types depending upon the duration of history and the presenting features. Acute sinusitis presents with a short history of 2-4 weeks as a part of upper respiratory tract infection. It may be viral or bacterial and it is accompanied by fever in almost all cases.

Sub-acute sinusitis presents with a progressive history, lasting as less as 2 to no more than 12 weeks. It usually occurs after an upper respiratory infection where a viral may turn into a bacterial infection. Recurrent sinusitis is when the sinus infection occurs 2-4 times a year but with a gap of at least 8 weeks. That means in between infections, the nasal and the sinus lining go back to their normal states.

And finally, chronic sinusitis is the term used when a sinus infection does not resolve completely and the symptoms remain for more than 12 weeks, with or without worsening of the condition.

Risk factors and Causes

As previously mentioned, blocking of the ostia leads to stasis and infection. The blockage is more possible when there is nasal congestion, such as in allergies, upper respiratory infections, chemical irritation, and local trauma; or with a mechanical obstruction, as in nasal polyps, deviated septum, foreign bodies and tumors.

A few genetic conditions impact the flow of secretions in the respiratory tract and sinuses, such as Kartagener syndrome, ciliary dyskinesia, and cystic fibrosis. This also leads to pooling of secretions and inflammation. Some immune deficiency syndromes also predispose the patients to infections, like combined variable immunodeficiency and immunoglobulin A immunodeficiency.

Pre-existing pulmonary diseases, such as asthma, COPD, also put the patient at risk of sinus infections.


The symptoms of both acute and chronic are similar with a few exceptions. The common ones are pain or pressure over the affected sinus, cloudy to yellowish-green nasal discharge, and nasal congestion.

The maxillary pain is mostly on the face, felt over cheeks, upper jaw and forehead. Bending forward or straining worsens the pain. Along with these, acute sinusitis may present with fever, headache, redness over the sinuses, and pain on touching the upper-inner side of eye socket; whereas chronic infections may present with post nasal discharge, reduced sense of smell, blocked nose, bad breath, ear fullness, stuffy voice and a persistent cough.


Acute sinusitis is managed with adequate draining of the affected sinus and antibacterial cover where necessary. To help relieve symptoms:

  • Nasal irrigation with distilled water or with saline solutions is recommended
  • OTC brufen and decongestants, antihistamine sprays are advised to relieve pain, Antihistamines sprays can worsen the sinus congestion if used for long periods.
  • Occasionally the doctor may give a steroid spray for congestion relief, especially in allergies (these do not cause rebound congestion.)
  • Steam inhalation, humidification, and warm compresses to forehead and cheeks also help drain the sinuses.
  • Ample hydration, rest, balanced diet, and warm drinks, especially soups, help the body to heal.
  • Smoking and irritation of the nasal tract should be avoided.
  • Herbal remedies for clearing up congestion are quite popular, such as inhalation of infused eucalyptus oil and tea tree oils.
  • Antibiotics are prescribed when the infection is bacterial, chronic or more likely to become bacterial in the presence of preceding factors.
  • For unresolving infections, the doctor may advise an X-ray or a CT scan to assess the infected sinus, a mucus culture or a biopsy to identify the cause.
  • Some unresolving sinusitis require surgical treatments to remove the blockages, expand the ostia, and occasionally clean the sinus manually.

Prospective view:

Preventing rhinitis and keeping the ostia clear in the nose and can help protect against sinus infections. Steps include:

  • Avoiding nasal and sinus irritants, such as smoke, soaps
  • Keeping allergies under control, avoid allergen exposure and use of antihistamines
  • Washing hands frequently and effectively
  • Maintaining moisture and hygiene of the sinus and nasal passages.

Most of the acute cases resolve with conservative management, without the need for antibiotics. These are usually related to viral or allergic infections and tend to resolve with mild interventions. Chronic and severe infections need proper treatments and specialist reviews.

Complications include worsening of the infection and spread of infection to involve other close organs like meninges and brain. Worsening symptoms include high grade fever, unresolving headache and facial pain, colored or blood stained nasal discharge, confusion, neck stiffness, or changes in vision. These require urgent doctor’s review. This is also true for cases where there’s a predisposing disease(as mentioned above), or recurrent symptoms.


Viruses cause colds and flu, which form the stepping-stone for sinus infections. Sinusitis-like symptoms can occur during a cold or flu as well.

Sinus infections can be contagious and they can be spread by sneezing or coughing, and by touching anything with the hands the patient sneezed or coughed on.

Every sinus infection does not need an antibiotic. Viral infections resolve after the course of disease unless the immune system is compromised.

The sinuses are also indirectly connected to the ears, so a clogged sinus can cause earache, pressure in ear, reduced hearing and dizziness.

Trying to forcefully clean the nose may damage the nasal lining. Blowing gently into a tissue, one nostril at a time, after rinsing with a saline solution can help clear up the nose.


Nasal and sinus infections go hand in hand. Keeping the nose and sinuses clean and maintaining the moisture prevents from a lot of diseases. Sinusitis takes up to 6 weeks to resolve and the treatment is dependent on the type of sinus infection. Most of the time, conservative treatment is all that’s needed.

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