Sinus Infection Symptoms, Causes and Complications!

Introduction -

Sinus infection or sinusitis is an inflammation of the tissue lining the sinuses. The sinuses are four paired hollow cavities within the bones between the eyes, behind cheekbones and in the forehead. They are joined by a narrow channel. The sinuses produce thin mucus that drains out of the passages of the nose and keeps it moist. This mucus drainage aids in protecting the nose against dust, allergens and pollutants. 

A sinus infection takes place when the sinuses which are normally filled with air get filled with fluid. When that happens, germs can grow and trigger an infection. This infection is also termed as rhinosinusitis, where ‘rhino’ means ‘nose’.

A sinus infection is usually caused by a virus. But in certain cases, a bacteria or fungus may cause it.

Sinus infection symptoms

Sinus symptom image by Dr GVK Chaitanya Rao

A sinus infection can affect anybody. But one is more likely to get an infection if he/she has:

  • Common cold
  • Blocked drainage ducts
  • Nasal allergies
  • Nasal polyps
  • Asthma
  • Abnormal nose structure
  • Smoking habits
  • Immune system deficiencies

According to the National Institute of Allergy and Infectious Diseases (NIAID) India is significantly distressed by sinus infection or sinusitis. It is estimated that 134 million Indians suffer from chronic sinusitis.

The common signs and symptoms of can be listed as:

  • Pain in forehead
  • Pain on either side of nose
  • Pain in upper jaws and teeth
  • Pain between eyes
  • Tenderness in the face
  • Nasal discharge
  • Post nasal drip
  • Pain in ears
  • Nasal congestion
  • Sinus headache
  • Throat irritation and cough
  • Sore throat
  • Hoarse voice
  • Fever
  • Tiredness
  • Bad breath (halitosis)

Potential causes of sinus infection

A viral infection is caused by a virus infecting the lining of the facial and nasal cavities. While a bacterial infection is caused by a bacteria infecting the lining of the facial and nasal cavities. A bacterial infection often starts in the nasal cavity before spreading to the sinuses.

It is hard to determine whether a sinus infection is viral or bacterial based solely on symptoms or an exam. To identify the source of the sinus infection, an ENT specialist looks largely at the duration of the symptoms. A viral infection lasts for five to seven days and then starts to improve. On the other hand a bacterial infection lasts for seven to 10 days or longer and can worsen after seven days.

Allergies are usually defined as amplified sensitivity to a foreign substance also known as an allergen. The presence of an allergen causes the body’s immune system to defend itself. Generally the immune system only reacts if a harmful substance attacks the body.

An allergy can trigger a sinus infection when the sinuses tend to swell up in reaction to allergens like bacteria and other pathogens getting trapped in the nose.

The septum which divides the nostril is made of a piece of cartilage in the front and a bone in the rear. Generally a septum is centered but can be deviated to one side due to birth anomalies or injuries and can lead to sinusitis.

Apart from this, inherited anatomical differences can also make one prone to developing sinus infections. For instance, undersized facial features can restrict structures in the face and cause difficulties for the sinus drainage. This condition is often seen in children who by nature have smaller sinuses and nasal airways.

Occasionally environmental factors too play a vital role in causing sinus problems. Things like smoke, pollution and fumes can aggravate the sinuses and give rise to an infection or a congestion.

Stages of sinus infection

  1. Acute sinusitis – It is the first stage of sinus infection and typically lasts for a short period of time. In acute sinusitis, the symptoms start suddenly and can last up to 4 weeks. The primary cause of acute sinusitis is seasonal allergies.
  2. Subacute sinusitis – In subacute sinusitis, the symptoms can last up to 4 to 12 weeks. It is predominantly caused by allergies and bacterial infections.
  3. Chronic sinusitis – Sinus infection that lasts 12 weeks or longer is termed as chronic sinusitis. It is commonly seen in people suffering from constant allergies or structural abnormalities.

Will a sinus infection go away on its own?

Most of the time, infections get better on their own. But if it lasts more than 3 weeks, then medicines can help to cure the sinus infection.

The factors that can affect the duration of an infection can be summed up as:

  • Allergic rhinitis or hay fever
  • Nasal polyps
  • Deviated nasal septum
  • Weakened immune system (like HIV or AIDS)
  • Facial fracture that curb the nasal passages
  • Congenital diseases (like cystic fibrosis)
  • Asthma
  • Smoking and exposure to secondhand smoke
  • Common cold

How to know if a sinus infection is serious?

  1. Severity of symptoms – Whether caused by a virus or bacteria, an infection can give rise to symptoms like mild headache, fatigue, weakness or a cough. Viruses are much more plausible to be the cause of a sinus infection compared to bacteria. Although a bacterial infection could be serious if it is associated with severe headaches, neck pain, excessive sleepiness or a change in mental state.
  2. Duration of symptoms – The duration of the symptoms of an infection generally depends on whether the cause of it is viral or bacterial. In the majority of cases, the symptoms of an infection start to ease after about 10 days. Usually one to two episodes of sinus infections a year is considered as normal. But more than four require immediate medical attention.
  3. Presence of fever or other systemic symptoms – Although not common, fever may appear with infection, like it does with many other types of infections. A fever occurring with infection usually falls in the low grade range. It acts as a signal that the body is fighting off a virus, bacteria or fungal infection.

How long can you ignore a sinus infection?

Untreated sinus infection image by Dr GVK Chaitanya Rao

Most of the time, an infection goes away on its own. But an infection that continues for weeks without any treatment can lead to serious complications like:

  • Decreased or complete loss of the sense of smell
  • Breathing difficulties
  • Laryngitis (infection of the voice box)
  • Dacryocystitis (infection of the tear sac)
  • Orbital cellulitis/abscess (infection of the eye socket)
  • Cavernous sinus thrombosis
  • Meningitis
  • Subdural abscess
  • Frontal bone osteomyelitis (infection of the bone)
  • Brain abscess

The above mentioned complications can arise if a an infection is left untreated and can continue for months on end. Cases of mild sinus infections can be controlled at home using decongestants, sinus rinses and some good rest. But if they continue even after a week or 10 days, then it is recommended to seek medical treatment.

Consult Dr G V K Chaitanya Rao – Best ENT Doctor in Hyderabad and also the Best Sinus Infection Doctor in Hyderabad.

When to consult an ENT for a sinus infection?

Consult a doctor if:

  1. One is suffering from persistent or recurrent sinus infections – When an infection lasts more than three months or keeps coming back, it means that one is suffering from a chronic sinus infection. Some of the common reasons for getting an infection again and again are frequent colds, deviated septum, allergies, nasal polyps, asthma or exposure to environmental pollutants.
  2. One has severe symptoms or complications – Usually an infection occurs after an upper respiratory tract infection like a cold. One may start showing severe symptoms like nasal discharge, blocked nose, sinus headache, high fever, bad breath or reduced sense of smell.
  3. One has structural abnormalities of the sinuses – In general the anatomical variations are divided into three categories like structural abnormalities, pneumatization and supplementary openings. The structural variations which are most commonly associated with the infection are septal deviations, true conchae bullosa and supplementary maxillary ostia.


Chronic sinusitis does increase the risk of other respiratory issues as the linings of the nose and sinuses are similar to that of the lungs. People suffering from chronic sinusitis and nasal polyps are most likely to have asthma also. Severe symptoms include nasal congestion, pain and pressure in the sinuses, wheezing, chest tightness and cough.

As in sinusitis, the mucus drainage gets blocked, bacteria starts to grow. The most prevalent viruses and bacteria that trigger sinusitis can also cause the flu and certain kinds of pneumonia.

A sinus infection can spread over the borders of the sinuses infecting the eye, brain or bone. Untreated sinus infection can hinder how one’s brain and eyes function.

Even though there are various barriers protecting the brain, sometimes bacteria can pass through. The reason for this is that the space between the sinuses and the brain is very less. It makes it easier for the sinus infection to spread to the brain. If the brain gets affected with sinus infection, one will start experiencing swelling, seizures, vomiting and abnormal mental health.


The paramount reason to seek treatment for a sinus infection is to live a healthy life with symptoms either controlled or eliminated. Treatment will reduce sinus inflammation, make drainage easier and eradicate any infection. In exceptional cases, untreated sinusitis can lead to meningitis, a brain abscess, or an infection of the bone.

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Medically reviewed by SinusDoctor,
Dr G V K Chaitanya Rao

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