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Overview: Sinusitis

Last Update: February 23, 2021; Next update: 2024.


Sinusitis is an inflammation of the membranes lining the paranasal sinuses (air-filled spaces around the nose) and the nose itself. It is also known as "rhinosinusitis." "Rhino-" means nose, and "sinus" means a space in the body.

The paranasal sinuses are part of the upper airways, and are connected to the nasal cavity. They are made up of several cavities (spaces) in the skull found from the forehead down to the teeth of the upper jaw. Depending on where they are, these cavities are known as the frontal sinuses, the sphenoid sinus, the ethmoid sinus and the maxillary sinuses. The paranasal sinuses are lined with mucous membranes that have tiny hairs on them (ciliated epithelium). These mucous membranes produce a secretion (fluid) that drips down through the nose and throat.

At a glance

  • Sinusitis is an inflammation of the paranasal sinuses (air-filled spaces around the nose).
  • It is painful and makes it harder to breathe through your nose.
  • Steroid nasal (nose) sprays can relieve the symptoms.
  • Painkillers and nasal rinses sometimes help too.
  • Surgery is only considered if you have severe, chronic symptoms and if no other treatment has worked.
Illustration: Position of the sinuses – as described in the article

Paranasal sinuses

Sinusitis can be acute or chronic: The acute form may occur several times a year, but it always goes away within several weeks at the latest. It is considered to be chronic sinusitis if the symptoms continue for more than three months.


Sinusitis usually causes the following symptoms:

  • a stuffy nose
  • difficulty breathing through the nose
  • a reduced sense of smell
  • pain and pressure in your face

Sometimes it leads to a fever and headache too.

Sinusitis causes your nasal passages to become blocked due to the swelling and build-up of fluid. This makes it more difficult to breathe through the nose, which feels stuffy. A yellowish or greenish discharge is a sign of bacteria.

Sometimes the pain radiates from the sinuses to other parts of the head. It is often felt around the forehead, the upper jaw, the eyes and – less commonly – the teeth (toothache). The pain and stuffy feeling usually gets worse if you lean forward, for example when getting up out of bed. Sense of smell is often reduced or may even disappear completely.


Acute sinusitis is often brought on by a cold or flu. Colds are usually caused by respiratory viruses, and only rarely by bacteria. But people who have a cold that is caused by a virus may get a bacterial infection on top of that.

Viruses or bacteria trigger an inflammation, which causes the mucous membranes to swell up. This may prevent fluid from draining from the sinuses. If that happens, the fluid becomes thicker and the sinuses fill up with thick, often yellow-green mucus.

It is often not known what exactly has caused chronic sinusitis. Sometimes it develops from acute sinusitis that has not cleared up properly. Other factors can increase the risk of developing chronic sinusitis or make it worse. They include:

  • Allergic rhinitis (an allergy-related inflammation inside the nose)
  • A deviated nasal septum (where the wall between the two nostrils is bent to one side) or other abnormalities in or near the nose
  • Taking acetylsalicylic acid (the drug in medications like Aspirin) if you have an intolerance to it

Chronic sinusitis is also more likely to develop in people who have a weakened immune system, for instance as a result of taking certain medications. Environmental factors such as chemicals or cigarette smoke can play a role too.


Acute sinusitis usually goes away again within one or two weeks. In rare cases, it leads to complications or lasts several months. Chronic sinusitis can lead to nasal polyps (mucous membrane growths). These make it more difficult to breathe through your nose and can reduce your sense of smell.

In very rare cases, the inflammation may spread to nearby parts of the body, like the eyes or brain. Signs of this include a high fever, swelling around the eyes, inflamed and reddened skin, severe facial pain, sensitivity to light and a stiff neck. If you have these symptoms, it’s important to seek medical advice immediately – either at a doctor's practice or hospital.


Your doctor will first ask about your symptoms and then gently tap and press certain parts of your face with their hands to see if it hurts. A tube-like device with a small lamp on it (endoscope) can be used to take a closer look at the inside of your nose and see whether the membranes are swollen, for instance. In rare cases, a sample of the secretions is taken and tested for germs in a lab. This is done by inserting a probe into the nose. If the sample isn't enough to provide a clear diagnosis or if there are signs of complications, a computed tomography (CT) scan or ultrasound scan can be done.

Finding out whether sinusitis is caused by bacteria or viruses involves quite a lot of effort and usually isn't necessary. In acute sinusitis, it hardly makes a difference to the treatment that is recommended anyway.

It can be helpful to do an allergy test in chronic sinusitis. This is because chronic sinusitis often occurs together with an allergy.


Steroid nasal sprays can relieve the symptoms of both acute and chronic sinusitis. Decongestant (anti-swelling) nasal sprays only help over the short term, if at all. They shouldn't be used for longer than a few days. A nasal rinse or inhalation also helps in some people. It only rarely makes sense to use antibiotics.

In chronic sinusitis, treatment with biologics may be considered. Dupilumab is the only biologic that has been approved for the treatment of sinusitis in Germany. It can reduce the inflammation in the membranes lining the nose and sinuses, and is injected under the skin.

Some people who have chronic sinusitis choose to have surgery to widen narrow passageways in their sinuses. This is an option if other treatments haven’t helped enough.

Further information

When people are ill or need medical advice, they usually go to see their family doctor first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.


© IQWiG (Institute for Quality and Efficiency in Health Care)
Bookshelf ID: NBK279485


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