• Acute sinusitis (also known as rhinosinusitis) is self-limiting and usually triggered by a viral infection of the upper respiratory tract (for example, a common cold).

  • Only about 2% of cases are complicated by bacterial infection, but it is very difficult to distinguish these.

  • Symptoms can last for 2 to 3 weeks – most people will get better within this time without treatment, regardless of cause (bacteria or virus).

  • Antibiotics are not needed for most people. The number of people improving with antibiotics is similar to the number getting adverse effects, such as diarrhoea.

  • Complications of acute sinusitis are rare (about 2.5 to 4.3 per million people per year). Withholding antibiotics is unlikely to lead to complications.

  • Previous antibiotic use may lead to resistant organisms if the same antibiotic is used again.