When your sinuses are clear, you breathe in and out easily, and you never think about all the mucus production and air-conditioning occurring inside your nasal cavity. Then one day, you notice you’re congested, and after several days or weeks, you start to feel pressure in your face or forehead. You hope it will go away, but instead you eventually find yourself so stuffed up or in so much pain you need to call your doctor.

Although there are many causes of sinusitis, most fall into one of three broad categories: anatomical, genetic, and environmental.

Causes of sinusitis

Anatomical Genetic Environmental
Deviated septumNasal fracture

Nasal polyps

Scar tissue


Cystic fibrosisImmunodeficiency disorders

Primary ciliary dyskinesia

Triad asthma

Air pollutants/chemicalsAllergies

Cigarette smoke


Dry indoor heating systems

Microorganisms (bacteria, fungi)

Sick building syndrome

The warm, moist environment of the clogged sinus serves as what biologists refer to as the perfect culture medium. Even when you’re healthy, small quantities of bacteria live in your nose and sinuses. But bacteria in the stagnant mucus rapidly multiply, so instead of a few hundred stray bacteria in your sinuses, you soon have several thousand, several hundred thousand, and eventually millions. Large numbers of bacteria constitute an infection.

Once your sinuses are infected, things quickly go from bad to worse. Your body kicks into action to fight the infection with what’s known as the immune response. Unfortunately, this normally beneficial process is what ultimately makes you miserable.

To fight the bacteria, your mucus-secreting glands shift into overdrive, cranking out even more mucus than normal. Equally important, the mucous membrane that lines your sinus swells as blood vessels dilate in preparation for battle against the bacteria. White blood cells enter through this membrane to attack and destroy the bacteria. The white blood cells and the bacteria release a variety of substances that further stimulate the inflammatory process.

A full-blown case of sinusitis is likely to worsen before it gets better. To fight the infection, the sinuses become more inflamed, which causes more swelling, which leads to more blockage, which allows for more bacterial overgrowth. You’re now stuck in the “sinusitis cycle,” which is only broken when the bacteria are eliminated by the body’s immune system, medications, or, occasionally, surgery. Once inflammation and blockages diminish, and the sinuses are draining normally again, you’ll feel great relief and breathe freely again.

The Sinusitis Cycle



How do I know if I have sinusitis?

A number of symptoms can occur during a sinus infection. The three most common are: pain and pressure, difficulty breathing and congestion, and postnasal drip.

Pain and pressure

Inflamed tissue presses on the nerve endings in the lining of your sinuses. This can cause:

  • Forehead pain or headache.
  • Cheek pain, which may radiate to the teeth in the upper jaw.
  • Pain between the eyes or across the bridge of the nose.
  • Pain behind the eyes, on the top of the scalp, or along the back of the head.


Difficulty breathing and congestion

The combination of swollen nasal membranes and excess mucus makes it difficult or impossible to breathe through your nose. This blockage can affect one or both sides of the nose—it can even alternate between sides.


Postnasal drip

Normally, small amounts of mucus from the sinuses drain into the nose and down the back of the throat before being swallowed. During an infection, increased mucous secretion by the nose and sinuses creates a larger volume of mucus, which is often thick and yellow or green. This mucus, flows down the back of the nose and throat. Some people blow a large amount of mucus out the front of the nose as well.


Other sinusitis symptoms

Other sinusitis symptoms can include any of the following:

  • Loss of smell. Swelling of the membranes in the nose can block odor molecules from reaching the smell receptors in the nose, leaving you with a reduced sense of smell.
  • Loss of taste. A normal sense of taste depends on an intact sense of smell. So, many people who lose all or part of their sense of smell from sinusitis also report a decrease in their sense of taste.
  • Bad breath. The bacteria and debris in the mucus typical of a sinus infection emit foul-smelling odors. When that mucus runs down your throat it may cause bad breath. Mouthwash is of limited help.
  • Cough. When mucus runs down the back of the throat, it may touch the vocal cords and trigger an involuntary cough response. Coughing is often worst upon awakening because mucus from the nose and sinuses pools in the throat overnight.
  • Sore throat. The mucus from a sinus infection is more acidic than normal watery mucus, so it can irritate the membranes that line your throat.
  • Fatigue. Your body uses extra energy to fight any infection. In addition, poor nasal breathing and frequent coughing during the night makes getting enough quality sleep difficult.
  • Ear fullness. Mucus drainage and inflammation from sinusitis may block the Eustachian tubes, passageways that connect your ears to the back of your nose. When these tubes become blocked, you can develop an uncomfortable feeling of fullness or pressure in the ears, similar to what you may experience when you’re on a plane descending from a high altitude.
  • Fever. Occasionally, a fever may accompany a sinus infection.


Making the diagnosis

Unless you’ve had sinusitis before, it can be hard to distinguish it from other ailments, such as colds and allergies. People often mistakenly confuse the three because so many of the symptoms are similar. But they are, in fact, different entities with different causes:

  • Colds. Whereas sinusitis is caused by bacteria, colds are caused by viruses. The body’s immune system is usually quite effective at controlling viral infections, so most colds go away within a week. Colds can occur at any time but are most common during winter (the cold season). However, a cold can precede a sinus infection.
  • Allergies. Allergies are usually caused by environmental irritants, such as pollen, dust mites, or pet dander, not bacteria or viruses. These irritants, known as allergens, activate an immune response that is different from the immune response to an infection, and includes repeated sneezing and itching of the nose and eyes. Allergies can occur year-round, or be seasonal. Seasonal allergies tend to be worst during the spring, when flowers and trees bloom, and the fall, when ragweed is in the air. Allergies, like colds, may precede and trigger sinusitis.


Seeing your doctor

Your primary care physician will ask you to describe your symptoms and how long you’ve had them. In addition to pain and pressure, difficulty breathing and congestion, and postnasal drip—she will probably inquire about other symptoms, such as loss of smell, sore throat, cough, and fatigue. She will also ask about your history: Have similar symptoms occurred in the past? How often? What medications have you tried? Do you have allergies? Do you smoke? What are your home and work environments like?

Try to be prepared to answer these questions as thoroughly as possible. A good patient history is the single most important tool your doctor has to confirm the diagnosis of sinusitis. Once the history is completed, your primary care physician may look inside your nose with a small flashlight. She won’t be able to see into your sinuses, but this can help her assess how much swelling there is and whether any pus is present.

Some doctors may also tap on your forehead or cheeks—a technique known as percussion of the sinuses—and ask you if it hurts. Although there’s no harm from tapping, you should be aware that it’s not a reliable indicator of sinusitis. Many patients who have sinusitis have no sinus tenderness during an infection, while others with completely normal sinuses will complain of pain when their forehead or cheeks are tapped.

A careful patient history with a nasal examination is usually enough to determine whether you have sinusitis. In some cases, a doctor may recommend additional tests to confirm the diagnosis.



Recent studies have suggested that most patients with acute sinusitis will get better on their own without the need for antibiotics. Over the counter medications, such as decongestants, mucus-thinning agents, or pain relievers—can help control symptoms while the body’s immune system fights off the offending bacteria and the sinus inflammation resolves.

In cases of chronic sinusitis or infections where symptoms persist for longer than a week, many primary care physicians will prescribe an antibiotic. If your doctor suspects that allergies are contributing to a sinus problem, she may also prescribe a nasal steroid spray and recommend an antihistamine.

A course of antibiotics will often eliminate the infection or at least reduce it to the point that your symptoms recede. But if the sinus blockage remains, the infection may return a short time later. If you have more than three sinus infections in a year, your primary care doctor may refer you to an ear, nose, and throat (ENT) specialist, also known as an otolaryngologist.

Off to the ear, nose, and throat (ENT) specialist

Like a primary care physician, an ENT doctor will begin by asking you about your history of sinusitis. Next, he will likely examine your nose, using a nasal speculum to gently spread your nostrils and look inside. If he wishes to get a closer view, he’ll use an endoscope, a thin, high-resolution telescope with a light on one end and an eyepiece or camera on the other.

Nasal endoscopy is mildly invasive, so he’ll first spray your nasal passages with a topical decongestant (which enlarges the nasal passages by temporarily reducing swelling in your mucous membranes) and a mild topical anesthetic (which reduces the tickle sensation and prevents you from sneezing). These medications help ensure that endoscopy is not painful, although some people may still find it mildly uncomfortable.

Endoscopy enables an ENT specialist to view the areas inside your nose where the sinuses drain, but it does not allow her to look inside the sinuses. To learn what’s going on inside the sinuses, your ENT doctor will probably suggest a sinus CT scan, if you haven’t already had one.


Other tests

In almost all cases, a detailed patient history, nasal endoscopy, and a CT scan will provide your ENT doctor with all the information he needs to make an accurate diagnosis. Occasionally, though, additional tests are ordered.

  • Allergy tests. If environmental allergies appear to be the underlying cause of your sinusitis, you may be a candidate for allergy testing (skin tests, blood tests, or both).
  • Cultures. If endoscopy shows pus, an ENT specialist may take a small sample to determine which bacteria are present and how sensitive they are to various antibiotics. This may be particularly helpful for patients who have not responded as expected to antibiotics.
  • Blood tests. Your physician may order general blood tests if he suspects you have a systemic (whole-body) illness that’s triggering your sinusitis.


Antibiotics: The mainstay of treatment

In most cases, antibiotics eliminate the infection-causing bacteria, allowing inflamed nasal mucous membranes to shrink and your sinuses to drain. You typically notice an improvement in symptoms within forty-eight hours. Pain subsides, swelling goes down, and thick mucus becomes thinner. You may note a temporary increase in postnasal drip—a sign the antibiotic is working.

Unfortunately, antibiotics sometimes fail to do away with the offending bacteria or provide only temporary improvement, and symptoms return quickly. Also, antibiotics can be expensive and they have side effects.

With a severe infection that fills a sinus cavity with mucus or pus, there may not be an adequate blood supply in the center of the sinus to deliver the antibiotic. Bacteria living in the fluid may continue to multiply, so it takes weeks, instead of days, to kill enough bacteria to allow the sinuses to fully open and drain the offending microorganisms.

Also, antibiotics sometimes fail because bacteria are resistant to them. If an infection fails to show signs of improvement after ten days or if an infection goes away but comes back within a few weeks, your doctor has two options: having you take the first antibiotic again for a longer period of time or trying a different antibiotic that kills a larger variety of bacteria. For chronic sinus infections, it’s not unusual for an antibiotic to be prescribed for three or more weeks. To improve the likelihood of success, it’s important to take all the medication as prescribed.

Sinusitis and antibiotic resistance

Researchers are engaged in an ongoing battle against the army of bacteria; newly developed antibiotics are initially effective but lose effectiveness over time as resistance develops. The biggest problem contributing to resistance is unnecessary use of antibiotics. For example, they’re often needlessly prescribed for the common cold, which is caused by a virus, not bacteria. Antibiotics are not effective against viruses. Sinusitis, on the other hand, is caused by bacterial infection, so antibiotics have a legitimate role in its treatment.


Minimizing side effects

All antibiotics put you at risk for side effects, with the broad-spectrum antibiotics tending to have more severe side effects. Your doctor will likely discuss side effects for any antibiotic he or she prescribes. The most common ones include:

  • Allergic reactions. True allergic reactions in which people’s immune systems are triggered into action when they take antibiotics are rare, accounting for only 5%-10% of all side effects. But these reactions can be severe. The most serious allergic reaction involves the onset of hives, swelling of the throat, and difficulty breathing shortly after taking the medication. These symptoms, known as anaphylaxis, require immediate treatment in an emergency room.A more common but less serious allergic reaction from antibiotics is the development of a rash. Most rashes occur within a few days of starting the medication. If you develop a rash, stop taking the antibiotic immediately and inform your doctor.
  • Stomach problems. Gastrointestinal disorders, including nausea and diarrhea, are the most common side effect of antibiotics. Such problems are more common with cephalosporins, macrolides, and quinolones than with penicillins.Diarrhea can occur because in addition to killing the bacteria in your sinuses, antibiotics do away with bacteria in your bowel that help you digest food. GI side effects tend to be worse on an empty stomach, so taking antibiotics with food can help you avoid or lessen these side effects. Eating a six-ounce cup of yogurt once or twice a day, which replenishes bacteria that aid in digestion, can also be helpful.
  • Yeast infection in women. Antibiotics also may alter the balance of microorganisms that normally reside in the vagina. Antibiotics suppress bacteria that have an antifungal effect, resulting in an overgrowth of yeast. Antifungal medications to treat such yeast infections are available over the counter in topical ointments and by prescription in pill form.
  • Sensitivity to sunlight. While taking a quinolone antibiotic, your skin is unusually susceptible to sunlight. If you’re exposed to the sun while taking this type of antibiotic, you may suffer a particularly bad sunburn, so be sure to take precautions (avoiding peak sun hours, use sunscreen, wear a hat, etc.)
  • Unpleasant taste. Some types of antibiotics can cause a metallic taste.
  • Drug interactions. Antibiotics may interact with other drugs you’re taking, particularly blood pressure, blood-thinning, and seizure medications. Always inform your physician of any and all medications you take.
  • Effects on pregnancy. All medications, including antibiotics, present a risk during pregnancy. Your obstetrician can advise you on which antibiotics are considered safest during pregnancy.

Short- and long-term use of antibiotics

A typical course of antibiotics for sinusitis lasts from 10-14 days. For more severe infections, the course can be extended to three to six weeks. However, in some circumstances, patients may benefit from antibiotic regimens that are either shorter or longer than the typical course.

On the short end are the newer, powerful antibiotics that come in three- and five-day packages. Such short-dosing regimens are effective for people with acute sinusitis as well as those with chronic sinusitis who experience flare-ups. However, they may be less effective for severe infections.

At the other extreme is a low-dose, long-term strategy, which may be appropriate for patients who continue to develop sinus infections even after repeated courses of antibiotics for conventional durations. Such regimens involve half the normal daily dosage and last for two to six months. In theory, keeping the bacteria count down for a long stretch allows time for inflamed mucous membranes to heal. The sinuses can then drain better, and the likelihood of future infections is reduced.


Other forms of antibiotics

Although antibiotics are usually prescribed in pill form, they don’t have to be. In special circumstances, they may be more effective when administered topically or intravenously.

In theory, topical application of antibiotics directly into the nasal and sinus cavities makes a lot of sense, because the medication is applied in a relatively high dose where it’s needed. Furthermore, side effects should be less than with oral antibiotics, because the medication does not pass through the stomach or bloodstream.

With a doctor’s prescription, special pharmacies create an antibiotic solution and ship it to you with a nebulizer, which delivers the medication in a suspension of tiny droplets inhaled through the nose. If you frequently use antibiotics, you may wish to ask your physician about this method.

Some antibiotics are available as ointments that can be applied inside the nose.

Intravenous (IV) administration of antibiotics is only considered for the most severe sinusitis cases.


Diet, lifestyle, and your sinuses

Food allergies: Milk and wheat

Although food allergies that trigger sinusitis are relatively rare, they may be the culprit in people whose symptoms cannot be explained by more common causes. The tip-off that such an allergy may be present is when postnasal drip is the primary symptom. If you are particularly bothered by such drainage—or constant collection of phlegm in the back of the throat, especially upon awakening— you may have a food allergy and not even be aware of it.

What causes food allergies is not well understood, but it’s clear that when certain people eat specific foods, undesirable reactions occur. In some cases, such as allergies to shellfish or peanuts, these effects can be immediate, resulting in hives or swelling of the face or throat. In severe cases, these allergic reactions can be life-threatening.

In most cases, however, the effects are more subtle. Symptoms have a gradual onset and are less marked, to the point where people often do not make the connection between the food and the subsequent reaction it causes.

Milk and wheat are the two foods that most commonly cause the allergic reaction that leads to excess mucus production and troublesome postnasal drip. This drainage can also block the nose, impairing breathing and blocking the sinuses, prompting an infection.

Diagnosing food allergies can be a bit tricky, as there is no standardized approach used by all allergists and test results can be unreliable. The best way to determine if you have such an allergy is an elimination diet; in other words, you stop eating the suspect food for a period of time and see if that makes a difference. Two weeks is good, and four weeks is ideal—if you can hold out that long, then you’ll know with some certainty whether you’re really allergic.

During the trial, you have to be very strict in your diet. With milk, you need to cut out not just the milk you drink, but all products containing even small quantities of milk. That includes cheese, yogurt, and many baked goods. You’d be surprised at how many products contain small amounts of milk, including many breads, sauces, and salad dressings. You’ll have to check labels to be sure products are milk-free.

With wheat and wheat-based products, such as bread and pasta, the source of the problem is also a protein—in this case, one called gluten. Again, eliminating wheat for two to four weeks should reveal whether you have this allergy.

People with sinus problems who truly are allergic to milk or wheat often see dramatic symptom improvement when they eliminate the offending food.



It’s not uncommon for people with sinusitis to develop a new infection or see their symptoms flare up within twenty-four hours of drinking an alcoholic beverage. The problem is not the alcohol itself but the presence of by-products of the fermentation and aging process. Some of these substances have histamine-like properties. Similar to what happens with an allergic reaction to pollen or dust, individuals who are sensitive to these impurities can experience nasal congestion, drainage, and headaches.

You may have this alcohol sensitivity without knowing it. If you suspect you might, you can usually sidestep this problem by avoiding alcoholic beverages likely to contain high amounts of congeners. If you like wine, you’re better off with white wines, especially those processed in stainless steel containers, instead of red wines, which are aged in wooden barrels and contain many more by-products. If you drink liquor, you’ll have fewer problems with clear varieties, such as vodka (especially brands that are “smoother” and have been highly distilled), than with darker, aged liquors, like bourbon and scotch. In general, stick to lighter colored beer if that is your beverage of choice.



In addition to damaging your lungs, cigarette smoking impairs the function of the tiny hairs (cilia) in your nasal passages and sinuses that sweep out mucus and debris. When cilia don’t function well, mucus and bacteria build up in the sinuses, leading to infections. If you smoke, quitting is probably the single most important step you can take to improve your sinus symptoms—and protect your long-term health. Cilia are resilient, so after you quit smoking, their normal function returns, which often leads to fewer sinus infections.