Acute sinusitis: Can antibiotics help?

In acute sinusitis, antibiotics usually cannot help, because it is normally caused by viruses, not by bacteria. In a severe infection antibiotics are necessary, however.

Sinusitis is a condition which many people get more than once in their lives. It mainly affects people during the colder months of the year. It can be very painful and also cause other unpleasant symptoms that usually last several days, and sometimes weeks. Sinusitis is one of the most common reasons for sick leave from school or work.

Sinusitis is an inflammation of the paranasal sinuses. A more precise name for this illness is rhinosinusitis (“rhino-” meaning “nose”). In sinusitis, the mucous membranes lining the nose and the sinuses become inflamed. The paranasal sinuses are part of the upper airways and connected to the nasal cavity. They are made up of several cavities in the skull found from the forehead down to the upper jaw. Depending on where they are, they are known as the frontal sinuses, the sphenoid sinus, the ethmoid cells and the maxillary sinuses. There is a graphic of where the paranasal sinuses are in our fact sheet “Acute sinusitis”. Sinusitis usually affects the maxillary sinuses.

Sinusitis is often brought on by a cold. Colds are usually caused by respiratory viruses, and only rarely by bacteria. Additional bacterial infection may develop after a viral infection, however. 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 the viscous, often yellow-green mucus. Allergies, nasal polyps, a deviated nasal septum (when the wall between the two nostrils is bent to one side) or a weakened immune system can all make sinusitis more likely.

Sinusitis causes your nasal passages to become blocked, which makes it harder to breathe through your nose. A lot of people experience pain in their forehead, jaw and around their eyes, and – less commonly – toothache. The pain usually gets worse if you lean forward, for example when getting up out of bed. Sinusitis is often associated with a fever, cough and runny nose, and it makes people feel tired and groggy. It may be acute and soon disappear again, but in rarer cases it lasts longer and becomes chronic. You can read more about respiratory tract infections in the feature of the same name. You can find out more about chronic sinusitis in the fact sheet “Chronic sinusitis”.

Research on sinusitis treatment with antibiotics

Antibiotics are often prescribed to treat acute sinusitis. Researchers from the Cochrane Collaboration wanted to know how effective antibiotics are in the treatment of an inflammation in the maxillary sinuses (the most common form of sinusitis) in adults.

The Cochrane Collaboration is an international network of researchers that aims to analyze the results of clinical studies. The researchers analyze studies called randomized controlled trials. In these trials, volunteers are randomly divided into groups. One of these groups receives the treatment, while the other one is given a fake medication (placebo), no treatment, or another treatment. This makes it possible to find out what effect the treatment has on the health of the participants.

The Cochrane researchers found 59 randomized controlled trials, most of which compared different antibiotics with one another. Five of the trials, involving a total of about 630 participants, compared antibiotics with fake (placebo) drugs.  If symptoms did not improve within one or two weeks at the latest, the researchers considered the treatment to be ineffective.

Another group of researchers from the University Hospital in Basel, Switzerland, analyzed trials to see whether certain kinds of people benefited from antibiotic treatment more than others. They looked at whether the treatment is more likely to work if people have particular symptoms like yellow-green nasal mucus, which suggest that they have a bacterial infection, for example. The reason for this is that finding out whether sinusitis is caused by bacteria or viruses can end up involving quite a lot of effort. To do this, a sample of the nasal secretion is examined in the laboratory. If it were possible to diagnose the type of infection (viral or bacterial) without this kind of test, it would make it more likely that antibiotics would only be used when they really can help.

The chances of feeling better after two weeks improve only slightly

The Cochrane analysis of research on antibiotic treatment showed that maxillary sinusitis usually clears up on its own without antibiotics:

• In 83 out of 100 people who did not take antibiotics, sinusitis symptoms improved within the first two weeks.
• In 90 out of 100 people who took antibiotics, the symptoms improved within the first two weeks.

This means that an extra 7 out of 100 participants got better by taking antibiotics. In the trials that compared different antibiotics, none of the active ingredients researched was better than the other.

In some participants, antibiotics seemed to have caused stomach and bowel problems and skin rash: the data on this vary in the different trials between 2 and 23 out of 100. But only as an exception did the participants stop taking the drugs because of severe adverse effects.

Since there are other treatments for sinusitis and it usually clears up without antibiotics, too, the use of antibiotics in sinusitis is often questioned. What is more, the overuse and inappropriate use of antibiotics has led to an increase in the development of bacteria that are resistant to antibiotics in recent years. This means that antibiotics do not always work and some illnesses can no longer be treated as effectively. You can read more about the dangers and prevention of antibiotic resistance in the feature “Using antibiotics”.

If complications are likely, antibiotics are necessary

If someone has acute sinusitis, one option is to wait one to two weeks and see whether their symptoms get better on their own. If there is no improvement, they can see a doctor – such as an ear, nose and throat doctor.

The researchers’ conclusions from the trials apply to mild to moderate forms of sinusitis. People with very severe symptoms were not included in the trials. They often need to take antibiotics rapidly, because their symptoms may be a sign of a serious bacterial infection, which means that they have a greater risk of complications. Signs of a serious form of sinusitis include high fever, swelling around the eyes, inflammatory redness of the skin, severe facial pain, sensitivity to light and a stiff neck.

Antibiotics are not the only treatment available for sinusitis. Pain-relieving and anti-inflammatory medications, steroid sprays, decongestants and inhalations are often used too. You can read more about the causes, diagnosis and treatment options for sinusitis in the fact sheet “Acute sinusitis”.


Author: Institute for Quality and Efficiency in Health Care (IQWiG)


Next planned update: March, 2015. You can find out more about how our health information is updated in our text “Informed Health Online: How our information is produced”.

© IQWiG (Institute for Quality and Efficiency in Health Care)