viral infections that lead to sinusitis may be contagious; bacterial sinusitis is generally not. it’s important to remember that most viral upper respiratory infections (common colds) cause nasal congestion which may involve the sinuses. if the viral sinus infection lasts well past the normal duration of a cold viral sinusitis may be diagnosed. these viruses are highly contagious and likely to cause a cold in others who come in contact with them. bacterial sinusitis most often occurs as a complication of a viral common cold. bacteria that are normally present in the nose and throat take advantage of the viral infection to invade the inflamed sinus passages. these sinusitis-causing bacteria may be passed from person to person but won’t cause an infection unless the right conditions are present. unlike with cold viruses most people will not develop sinusitis even if they are exposed to the bacteria. are sinus infections contagious/ i don't know.
is sinusitis contagious?