The most common chronic disease in the U.S. doesn't involve the heart or the lungs, but it can lower the quality of the sufferer's life just as much as if it did. Sinusitis, an inflammation of the mucous membrane lining the sinuses, affects more than 30 million Americans in its chronic form. Briefer bouts of the condition, called acute sinusitis, are even more common.
Sinuses are the hollow air spaces in the front of the skull.
Because they open into the nose and share a continuous membrane with it, anything that stuffs up the nose can cause the sinus membrane to swell. That can block the sinus openings and prevent mucus from draining out. The trapped mucus then becomes a breeding ground for bacterial infection, which causes or complicates most cases of sinusitis. Problem is, the condition is often overlooked or mistreated. Distinguishing among colds, allergies and sinusitis can be tricky.