Is it an allergy or a sinus infection?

For too many of us, springtime is synonymous with congestion. The combination of lingering winter colds and air suddenly full of pollen conspires to make it the season of stuffy noses, runny eyes, aching heads—and frustrating attempts to rein them all in.

Effective treatment starts with knowing whether your symptoms stem from allergies, such as hay fever, or sinusitis, an infection of the air cavities surrounding the nasal passages that frequently develops as a complication of the common cold.

But knowing the difference can be hard since some symptoms can overlap. And even when you know the cause, there are so many treatments to choose from that it's easy to end up with something that doesn't help much or even causes more problems than it solves.

For example, millions of Americans are prescribed antibiotics for sinusitis even though the  drugs usually aren't necessary. The problem is so widespread that such organizations as the American Academy of Family Physicians and the American Academy of Allergy, Asthma, and Immunology recently started a campaign to discourage doctors from prescribing those drugs unnecessarily.

Allergy sufferers are often unsure of which drugstore products they should turn to or which lifestyle changes are most effective. That's unfortunate not only because it prolongs their misery but also because growing research suggests that inadequately controlled nasal allergies can worsen other health problems, notably asthma.

Sinusitis and allergies share certain symptoms, particularly nasal discharge and, in some cases, headaches. But there are several important differences (read Comparing the symptoms, below).

Usually, symptoms and medical history are sufficient for doctors to diagnose the problem. But certain tests can sometimes help confirm whether the congestion stems from allergies or a bacterial or viral infection. For example, a nasal smear that contains many white blood cells, called neutrophils, can suggest a bacterial infection, while few or no neutrophils can indicate a viral infection instead. And a nasal smear with many eosinophils, another type of white blood cell, can suggest an allergy.

Some doctors recommend CT scans of the nasal passages when they suspect sinusitis, but the allergy, asthma, and immunology group and the American College of Radiology now recommend against that, saying that scans are necessary only if you have frequent or chronic sinusitis or are considering sinus surgery.

Figuring out that allergies are the cause of your misery is an important step toward getting relief. But your work isn't done yet. You still have to choose the right treatment.

That's important, since allergic reactions in the nose may make the whole airway sensitive to future allergen exposure and vulnerable to infections and possibly asthma.

Here are some proven steps for controlling respiratory allergies:

• Know your triggers. Keep a diary to track when and where allergy symptoms strike. That can help you determine whether they stem from outdoor allergens, such as grass and ragweed pollen, or indoor allergens, such as cockroaches, dust mites, and pet dander.
• Limit exposure. For outdoor triggers, keep the windows shut, stay inside when pollen or outdoor mold counts are high, and wash your hands and face after spending time outside. For indoor allergies, use an air conditioner or a dehumidifier to reduce humidity to below 50 percent. Remove carpeting from bedrooms, wash rugs and curtains often, and vacuum regularly.
• Use the right medication. The best first choice is often a generic version of the antihistamines cetirizine, fexofenadine, or loratadine. All are available without a prescription and cost less than their brand-name versions (Zyrtec, Allegra, and Claritin, respectively). Those drugs are less likely to cause drowsiness than older antihistamines, such as brompheniramine, chlorpheniramine, and diphenhydramine. Some people respond better to one of the newer antihistamines than to others, so some trial and error may be necessary.
• Prescription steroid nasal sprays,  such as fluticasone (Flonase and generic) and mometasone (Nasonex), are very effective. But stop taking them if they cause irritation or nosebleeds.
• Consider allergy shots. Also called immunotherapy, they can be an option if the drugs above aren't sufficient or cause intolerable side effects. Researchers are investigating ways to make the therapy more convenient, such as less-frequent shots. But for now it still requires progressively larger doses of allergens, such as grass pollen, injected by your doctor at least once a month for several years. It also carries a slight risk of anaphylactic shock, so patients are required to stay in the doctor's office for observation for 30 minutes after an injection.  

People with sinusitis due to the common cold or other causes are often prescribed antibiotics. In fact, sinusitis accounts for 15 to 21 percent of all antibiotic prescriptions written for adults in outpatient care.

But most of them probably don't need the drugs. Here's why:

• They seldom help. Sinusitis usually stems from a viral infection, not a bacterial one—and antibiotics don't work against viruses. Even when bacteria are responsible, infections usually clear up on their own within a week. In a study of 166 adults with acute sinusitis in the Feb. 15, 2012, Journal of the American Medical Association, amoxicillin was no better than a placebo at reducing symptoms after three days. In general, consider antibiotics only if symptoms last longer than 10 days, worsen over time, or are very severe.
• They pose risks. Studies suggest that nearly 25 percent of people who take antibiotics experience side effects, such as a rash or, more commonly, diarrhea and stomach problems. In rare cases, they can cause severe allergic reactions, such as anaphylactic shock.
• They can breed super germs. Overuse of antibiotics encourages the growth of bacteria that can't be controlled easily with drugs. That makes you more vulnerable to antibiotic-resistant infections and undermines the usefulness of antibiotics for everyone.
• They're a waste of money. Not all antibiotics are expensive, but since doctors continue to write so many prescriptions for them, the total cost to the health-care system is substantial—at least $31 million a year. If you do need antibiotics, the best choice is often generic amoxicillin, which costs as little as $4 for a course of treatment and works as well as more expensive brand-name antibiotics.

Self-help measures and, if needed, over-the-counter drugs can help ease symptoms until sinusitis clears up, typically within a week or so. They include:

• Rest. That's especially important in the first few days, when your body needs its energy to fight the virus—and when you're most contagious.
• Warm fluids. Drinking them can help thin nasal secretions and loosen phlegm.
• Humidity. Warm, moist air from a bath, shower, or kettle can loosen phlegm and soothe the throat.
• Gargling. Dissolve half a teaspoon of salt in a glass of warm water to relieve painful swelling in your throat.
• Rinsing. Flushing your nostrils with saltwater might ease congestion. If you use a commercial nasal-rinse device, be sure to thoroughly clean it daily.
• OTC medication, but used cautiously. To reduce the risk of side effects, look for single-ingredient products that target the symptoms you want to treat.

For a stuffy nose, drops or sprays containing oxymetazoline (Afrin, Neosynephrine Nighttime, and generic) work faster and cause fewer side effects than oral decongestants. But they can cause rebound congestion if used for longer than three days. If the stuffiness hasn't eased by then, ask your pharmacist for pseudoephedrine pills (Sudafed and generic), which are nonprescription but kept "behind the counter" to prevent their use in making illegal drugs. Check with your doctor before taking any oral decongestant if you suffer from anxiety or have diabetes, heart disease, hypertension, or hyperthyroidism.

In general, don't bother with antihistamines. Older ones such as chlorpheniramine and diphenhydramine might help a little but can cause drowsiness, dry eyes and mouth, and urinary retention, and can worsen narrow-angle glaucoma. Newer antihistamines, such as loratadine (Alavert, Claritin, and generic), work well for allergies but usually don't help sinus symptoms.