
What is a sinus infection?
A sinus infection, or sinusitis, occurs when the sinus cavities become inflamed. The inflamed sinuses create blockages that prevent bacteria and viruses from being able to drain out. The build-up of bacteria and viruses is what causes the infection. Sinus infections affect millions of people each year, and they can either be acute (short-term) or chronic (long-term). If a sinus infection lasts longer than 12 weeks, it is considered chronic.