In this article:
The human skull contains four pairs of interconnected air-filled cavities around the nose, which are referred to as sinuses.

The largest pair is called the maxillary sinuses, and they are located in the cheekbones at a gap of about an inch.
Two smaller ones lie at the lower end of the midforehead and together make up the frontal sinuses. The remaining two pairs are deeper seated in the skull.
One of these pairs, known as the ethmoid sinuses, falls between the eyes and maxillary sinuses. The other lies behind the nose and is called the sphenoid sinuses.
The walls of these hollow cavities contain thin mucus-secreting membranes and are lined with tiny hair-like outgrowths called cilia.
All the sinuses open into the nasal cavity to enable free flow of air and mucus. The cilia push the mucus produced within the sinuses toward small openings that lead to the nose so that it can be drained out.
When the sinus tissue becomes inflamed due to an infection or allergy, the cilia are unable to function properly.
As a result, the normal flow of mucus is disrupted. The fluid discharge is trapped within the sinus cavity, making it a breeding ground for germs, resulting in an infection.
What is sinusitis?
Inflammation of the sinuses that blocks the drainage of mucus into the nose is called sinusitis.
It is usually caused by a bacterial infection, but the entry of certain viral and fungal pathogens in the respiratory tract can also trigger swelling of the sinus tissue.
People with a weakened immune system are naturally at a greater risk because they are less capable of warding off bacterial and fungal sinusitis.
Inflammation of the sinuses can also occur as an allergic response, which is referred to as “allergic sinusitis.”
Why do symptoms of sinusitis get worse during the night?
The symptoms of sinusitis get worse at night due to the following reasons:
- Lying down causes poorer drainage of the swollen tissues of the nose and sinuses along with the accumulation of mucus, which clears more easily when we are upright and awake.
- When the nose is blocked due to sickness, the affected individual mouth breathes, causing a dry and sore throat on waking up.
- Often, medicine is taken during the day every few hours, which may not be done when asleep. Hence, the affected individual may wake up feeling worse.
Does a sinus infection cause a bad smell in the mouth?
Mouth breathing and mucus dripping at the back of your throat (called postnasal drip) can both cause a bad smell in the mouth.
Does eye strain worsen or bring on a sinus headache?
A sinus headache is associated with pressure in the head and face, usually experienced during an acute sinusitis. This is very often confused with more common causes of headaches such as migraines.
Eye strain does not lead to a “true” sinus headache as such headache is caused by acute inflammation and blockage of the sinus cavities.
How is sinusitis managed?
- Most sinus infections, whether bacterial or viral, resolve on their own unless there are any predisposing factors. In fact, 70% of bacterial sinusitis resolve on their own.
- Like any illness, rest, plenty of fluids, and avoiding alcohol and cigarette smoke are important to recover quickly.
- There is a misconception that a headache on the forehead along with nasal congestion is a sinus headache.
The only time you can truly get a sinus headache is when you have acute sinusitis.
Migraine and other conditions that cause a headache can often be accompanied by nasal symptoms and are misdiagnosed as a sinus headache. - Nasal allergies or exposure to irritants can lead to a more sinus infection.
Using sinus rinses (such as a neti pot) is very helpful in reducing the number of sinus infections. This is also true for those who are suffering from chronic sinusitis. - Chronic sinusitis requires medical treatment of the underlying factors such as allergies, 3-4 weeks of antibiotics, trial of nasal steroids, and a referral to ENT specialist.
A CT scan is often done to help understand the anatomy of the sinuses and confirm the diagnosis of chronic sinusitis.
In this procedure, the exposure to radiation is low as the images are quick and no special contrast is needed in most cases.
However, the scan cannot differentiate between chronic sinusitis and acute sinusitis. - In some cases, maxillary sinusitis can be from dental causes as tooth roots can project into the floor of the sinus. An infected tooth or extraction of such a tooth can lead to sinusitis.
- Nasal polyps are associated with swelling of the lining of the nose and sinuses and look like small bags. These polyps can lead to nasal obstruction, poor sense of smell, and chronic sinusitis.
Can exercise help with the symptoms of acute sinusitis?
Not really. No physical exercise can help during acute sinusitis. Rest and hydration are important for recovery.
Can cold foods worsen the symptoms of a sinus infection?
Cold foods can temporarily worsen swollen nasal tissues and the accompanying postnasal drainage. Conversely, warm foods and soups can feel soothing and comforting.
What is the best way to unblock a sinus?
The sinuses are air-filled cavities in the head that drain from small holes called ostia.
Mucus drains out due to the special beating of the hair-like structures on the lining of the cells. Gravity can also have a role in the drainage of some of the sinuses.
If the ostia get blocked due to a swollen lining, the mucus accumulates and infection ensues. Here are some tips to unblock the sinuses:
- For acute sinusitis not requiring any antibiotics or not leading to complications, over-the-counter medications such as decongestants, antihistamines, and saline sprays or washes can be helpful.
- Steam inhalation is also a natural and helpful way to help drain out the mucus and unblock the sinuses.
- Oral decongestants can often lead to drying up of the mucus, making it harder for the mucus to flow out.
Additionally, overuse of oral decongestants, especially in older people and those with hypertension, can lead to worsening of high blood pressure. Hence, they should be used with caution. - Nasal decongestants such as oxymetazoline and phenylephrine can help to decrease the nasal congestion and aid in the unblocking of sinuses.
However, they should not be used for more than 3-5 days in a row as they can lead to rebound swelling. - In severe cases that may necessitate the use of antibiotics, the patient may be given a preliminary dose of oral steroids to decrease the swelling of the sinus lining.
This allows the antibiotics given thereafter to pass through more easily and also help unblock the narrow drainage pathways of the sinuses. - When severe complications such as abscess are seen, urgent surgery to unblock the sinuses and drain the infection is needed in addition to the medical treatment.
Should one take antibiotics for sinusitis?
Antibiotics should be given carefully as distinguishing between a viral sinusitis and bacterial sinusitis can be challenging.
Taking antibiotics when not needed can harm your body and can lead to higher cases of antibiotics resistance. One of the most common reasons for overprescription of antibiotics is sinusitis.
The following are the guidelines for when to consider using antibiotics for an uncomplicated acute sinus infection.
- Severe symptoms such as headaches and high fever
- Symptoms getting worse or not better by 10 days
- Patients with a history of allergies and sinus surgery or patients who are more prone to sinus infections
- Patients that may be flying or have worsening symptoms after a flight
Is surgery helpful in the treatment of sinusitis?
Sinus surgery is helpful in a majority of patients who suffer from chronic sinusitis and have failed medical management. There is 80%-90% quality of life improvement in such patients.
Smoking is deleterious to the lining of the sinuses and can lead to higher rates of infections and failure of surgery in such patients.
Some ENT surgeons recommend against surgery in a patient who has not given up smoking.
What makes some children prone to sinusitis?
Children are more prone to nasal congestion and drainage (which is hard to distinguish from sinusitis) as they get more colds and other respiratory problems.
Also, little children have sinuses that are not fully developed and are more prone to having inflammation/infection of the nose and adenoids.
Chronic cough from postnasal drainage, bad breath, and nasal congestion are clues to chronic sinusitis as young kids are not able to provide a history of facial pressure, etc. Acid reflux can also contribute to chronic sinusitis in younger children.
Should flying be avoided when suffering from sinusitis?
Flying with a sinus infection can make your condition worse and can also lead to ear pain/Eustachian tube dysfunction.
If flying with an infection, make sure to drink lots of fluids. Using nasal decongestants can help, and the physician should have a lower threshold to prescribe antibiotics.
What are the complications of an untreated sinus infection?
Most sinus infections will resolve on their own as mentioned above.
However, acute sinus infections can lead to serious complications in immunocompromised individuals or in a severe sinus infection from more virulent forms of bacteria.
Children are also more prone to having orbital complications of acute sinusitis than adults.
The complications of acute sinusitis (rare) are often related to the spread of infection to structures close to the sinuses such as the eyes and brain. Here are some of them:
- The infection can spread to the eyes, resulting in cellulitis. It is characterized by eye swelling or abscess (a collection of pus).
This is a fairly threatening complication that requires prompt treatment with IV antibiotics and sometimes even surgery.
The condition should not be confused with bug bites and allergic reactions, which can also cause eye swelling. - The infection can spread to the brain, which can present as meningitis (infection of the lining of the brain) or abscess.
- The infection can spread locally. Pott’s puffy tumor is a swelling on the forehead when the frontal sinus is blocked, leading to a local infection of the bone.
- Some bacterial infections can release toxins and lead to a shock-like syndrome – a condition known as toxicemia.
Less seriously and seen more commonly than the described complications is the development of acute sinusitis into chronic sinusitis.
How can one differentiate between bacterial infection and viral sinus infection?
This is a question that is hard to answer even by most doctors including ENT specialists. The notion that having green mucus means bacterial infection is not true.
The most common way of diagnosing bacterial sinusitis versus a viral one is the timeline as most sinus infections start as viral infections.
Often, bacterial superinfections are contracted, and if the sinus symptoms get worse after the first few days or if the symptoms are not better in 7-10 days, then antibiotics are considered.
The exception for starting antibiotics sooner are severe sinus infections, complications, and a history of recurrent sinusitis.
What is the difference between acute and chronic sinusitis?
Acute sinusitis is an infection of the sinuses that lasts for 3 weeks or less.
Chronic sinusitis is a sinus infection/inflammation that persists for more than 3 months.
A sinus infection that lasts between 3 weeks and 3 months is referred to as subacute sinusitis.
Can sinusitis be cured permanently?
Yes. Sinusitis can be resolved permanently if handled properly.
Our immune system can fight off most sinus infections as often they start as viral infections. In fact, 70% of acute bacterial sinus infections get better on their own.
In some individuals with a severe sinus infection or preexisting conditions, such as allergies, history of smoking, exposure to irritants, and anatomical predispositions, treatment with antibiotics is necessary. Otherwise, chronic sinusitis may develop.