A s many as 45 million cases of sinusitis are diagnosed each year -- and about nine times out of 10, the diagnosis is wrong.

Sinusitis, also called a sinus infection, is a bacterial infection of the sinus linings. Infection causes the lining to swell and interferes with the normal drainage of mucus. This results in congestion, headache, reduced sense of smell and/or taste, tenderness around the eyes, cheeks, nose and/or forehead and other symptoms.

The majority of patients who think (or have been told) that they have sinusitis actually have other conditions -- allergies, a cold or migraine headaches. Errors in diagnosing sinusitis are a leading cause of unnecessary treatments, including the use of antibiotics and even surgery.

CAUSES AND DIAGNOSIS

Behind the face, there are many small sinus cavities -- over the eyes, along and behind the nose, above the teeth, etc. The cavities have tiny holes (ostia) that drain into the nose. Anything that interferes with normal drainage causes mucus to accumulate. The mucus provides a rich medium for bacterial growth and infection.

Many people have anatomical abnormalities, such as a deviated septum, that inhibit drainage and make them vulnerable to sinusitis. Other causes include colds, allergies and other conditions that trigger congestion.

Most cases of sinusitis are acute, lasting one to two weeks, and get better on their own without medical treatment. Less often, sinusitis is chronic, lasting three months or more. Patients who get four or more cases of acute sinusitis annually also are considered to have the chronic form. Chronic sinusitis may clear up without treatment, but less often than the acute form.

Most people with sinusitis have a greenish nasal discharge, a fever of more than 100°, swollen lymph nodes and tenderness over the sinuses.

The only sure way to diagnose sinusitis is with a sinus puncture. The patient is given a local anesthetic. A needle is guided through a nostril into a sinus cavity to extract mucus. The mucus is examined in a laboratory for signs of bacterial infection. Other sinusitis tests include CT and MRI scans, though these aren’t as accurate as the sinus puncture.

TREATMENT AND PREVENTION

Doctors routinely prescribe oral antibiotics to patients who appear to have sinusitis, but subjects in studies who are given no treatment recover just as quickly as those given antibiotics.

The only effective treatments for sinusitis are intravenous antibiotics given for three days to a week in the hospital... or surgery to restore normal drainage in the sinus cavities. Few patients need these treatments because true sinusitis is rare.

However, most patients can control sinus discomfort, regardless of the underlying cause, and lower the risk of infection by reducing or eliminating congestion. Best approaches...

Drink at least eight glasses of water daily. It thins mucus in the sinuses and promotes normal drainage. This is especially important if you have a cold or allergy flare-up.

Don’t take over-the-counter antihistamines or decongestants. They dry mucus and impede normal drainage.

Ask your doctor about sumatriptan (Imitrex). This medication, typically prescribed for migraines, can relieve sinusitus symptoms, postnasal drip, nasal congestion, a sense of fullness/pressure in the face, etc. The drug is effective in about 75% of cases.

Irrigate with a neti pot. Available in natural-health stores, a neti pot looks like a small teapot. It is used to flush a saline solution through the nose, nasal passages and sinuses.

Flushing these areas once or twice daily when you’re congested can improve drainage and reduce symptoms -- or prevent sinusitis when you’re suffering from a cold or allergies.

Mix about one-third teaspoon of salt and a pinch of baking soda in one cup of lukewarm water. Pour the solution into the neti pot.

Rotate your head and tip it over a sink, then pour the solution into one nostril. Keep pouring until it flows out of the other nostril.

Spit out any fluid that enters the mouth. Then repeat on the other side.