Sinuses are hollow spaces in the bones around the nose that connect to the nose through small, narrow channels. The sinuses stay healthy when the channels are open, which allows air from the nose to enter the sinuses and mucus made in the sinuses to drain into the nose.
Sinusitis, also called rhinosinusitis, affects about 1 in 8 adults annually and generally occurs when viruses or bacteria infect the sinuses (often during a cold) and begin to multiply. Part of the body’s reaction to the infection causes the sinus lining to swell, blocking the channels that drain the sinuses. This causes mucus and pus to fill up the nose and sinus cavities.
You have acute sinusitis when there has been up to 4 weeks of cloudy or colored (not clear) drainage from the nose plus one or both of the following: (a) a stuffy, congested, or blocked nose or (b) pain, pressure or fullness in the face, head, or around the eyes.
Acute viral sinusitis is likely if you have been sick less than 10 days and are not getting worse. Acute bacterial sinusitis is likely when you do not improve at all within 10 days of getting sick or when you get worse within 10 days after beginning to get better.
Because sinusitis is treated differently based on cause: acute viral sinusitis does not benefit from antibiotics, but some patients with acute bacterial sinusitis may get better faster with an antibiotic.
Rosenfeld RM, Piccirillo JF, Chandrasekhar, SS, et al. Clinical Practice Guideline: Adult Sinusitis. Otolaryngol Head Neck Surg. 2015.