We've all had cold symptoms that linger on for weeks, leaving us wondering if we'll ever feel healthy again. Most of the time it's just a bad cold caused by a virus, or allergies. But nasal congestion that prevents the sinuses from draining properly can create a perfect environment for a bacterial infection and the development of sinusitis. More than 31 million Americans have at least on case of acute sinusitis each year, and a small portion of those people will go to develop chronic sinusitis, with symptoms lasting at least 12 weeks. Below, Dr. Jerry Schreibstein, president of the Massachusetts Society of Otolaryngology and a practicing ear, nose and throat physician in Springfield, Massachusetts, reviews the different kinds of sinusitis and how each type can be prevented and treated. What are the sinuses? The sinuses are air-containing spaces in the face that act as cushions for the brain in the event of trauma and also act to aerate and humidify the air that we breathe. The sinuses produce mucus that drains through the nose back down the back of the throat, and we typically swallow that mucus. What is sinusitis? Sinusitis is an infection or inflammation of the sinuses. It typically occurs a week or 10 days following an upper respiratory tract infection. The common cold is a viral infection that causes an inflammation of the nasal membranes. Those membranes, in turn, cause inflammation of the sinus openings. If the viral inflammation doesn't clear, the mucus that's produced in the sinuses backs up, the sinus gets obstructed and bacteria can infect those areas, and you get what we call a bacterial sinusitis or a bacterial rhinosinusitis, meaning that the nose and the sinuses are both involved. Chronic sinusitis is sinusitis with symptoms lasting longer than 12 weeks. Imaging tests such as CT scans are helpful for diagnosis in this situation. And the patient who gets repeat episodes of acute sinusitis would be labeled as having recurrent sinusitis or recurrent acute sinusitis. What are some of the symptoms of acute and chronic sinusitis? Acute sinusitis is manifested by pain, pressure, congestion, colored nasal discharge and pain in the upper molars. Headache, in and of itself, is not a sign of an acute sinus infection. There are many different reasons why people get headaches and nasal congestion. Migraines, tension headaches, trigeminal neuralgia, which is an inflammation of the nerve that innervates the cheeks, can all cause pain in the sinus area, but not necessarily be due to an infectious cause. Chronic sinusitis is the condition where there's a chronic congestion. There's often postnasal drip, altered sense of taste or smell and a chronic discharge. And by definition, those are symptoms that are lasting more than about 90 days. They may be associated more with pressure symptoms than true severe pain. What are risk factors for sinusitis other than an upper respiratory infection? Untreated allergy can lead to an infection. When someone has allergic rhinitis, the nasal membranes get swollen, the nose and sinuses produce more mucus and the small openings of the sinus get swollen shut, whether it be from allergy or from a viral upper respiratory tract infection. If the secretions in the sinus back up, you get secondary bacterial infection. Other things that can precipitate infections are anything that can cause nasal inflammation. This includes pollutants, secondhand smoke, and in children, chronic adenoid infections. Nasal polyps can cause obstruction of the outflow track of the sinus. If you have nasal polyps and you get an acute viral infection, it compromises the drainage of the sinus and then potentially causes an infection. How can people prevent sinusitis? There are ways that people can prevent the development of an acute sinus infection. You want to do things that help promote drainage of the sinuses. So you want to use a clean humidifier with a nice, warm steam mist. Over-the-counter saline sprays that are non-medicated are very helpful to promote secretions. Topical nasal decongestions, when used for two or three days, can promote drainage and improve the nasal obstruction. But when used for more than three days, they can be addicting and you can get a rebound effect. The other things that are useful to prevent an acute sinus infection are oral decongestants. I also recommend avoidance of some of the common over-the-counter cold preparations that contain antihistamines, which dry the secretions and prevent the sinuses from draining. I prefer to use antihistamines only when people have underlying allergy. For the patient with chronic sinusitis, non-allergic rhinitis due to environmental irritants such as secondhand smoke and topical nasal steroids can prevent swelling of the sinuses and the sinus membranes. And there have been some studies to suggest that using intranasal steroids is useful for acute sinusitis. But that has to be done under a physician's supervision. How is acute sinusitis diagnosed? The most important thing is always listening to the patient and taking a good history. The doctor should make sure the patient has had an upper respiratory tract infection that's lasted for seven to 10 days or has been worsening after seven days, or that they've had allergy. When doctors examine the patient, they look for colored nasal discharge in the nose; pain in their teeth; pain or tenderness in their cheeks; and pain between the eyes or tenderness on the frontal sinuses over the eyes. I typically do not recommend X-rays to make the diagnosis of acute, uncomplicated sinusitis. Nasal endoscopy, which involves a fiber optic instrument that enables the doctor to examine the nose and sinuses, is very helpful to make the diagnosis for a patient if you cannot find nasal discharge on exam. It's also useful for someone who has had chronic sinusitis where you want to look at the openings of the sinus and get a culture to see what is the cause of that infection for someone who's already been on several antibiotics. How is sinusitis treated? Typically, 10- to 14-day course of antibiotics would be given for an uncomplicated, acute bacterial sinusitis. The most important thing in treating chronic sinusitis is to try and identify and eliminate the underlying cause such as an underlying allergy to pets or mold. Do they have anatomic problems in their nose that might predispose to chronic sinusitis? These could include nasal polyps, septal deviation and, in children, adenoid inflammation. The mainstay of treatment for chronic sinusitis is using saline washes to flush the nose out, using intranasal steroids when appropriate and, oftentimes, prolonged courses of antibiotics are indicated prior to considering surgical intervention. For patients who have been treated with appropriate medical therapy and are still having symptoms, endoscopic sinus surgery should be considered.