You probably expect colds and flu to be making the rounds during the chillier months of the year. But some other common viral infections can also crop up during winter. Here’s what you need to know about three comon viral infections you may encounter over the next few months:

Sinusitis

This painful condition develops when an infection, usually a virus from a cold, spreads to the cavities behind your eyebrows and cheekbones and between your eyes. You may have a stuffy nose with discharge, facial pain and pressure, or a sense of fullness in the sinus cavities.

Avoid it. Protect yourself from colds (one of the most common viral infections) by washing your hands (watch video below) well and frequently, eating a proper diet, and getting regular exercise and sufficient sleep. Reduce your exposure to cigarette smoke, too.

If you think you have it. Rest as needed. Drink warm fluids, which can help loosen mucus. You can also try an over-the-counter nasal saline rinse. OTC decongestant nasal sprays such as oxymetazoline (Afrin and generic) may help unblock your nose, but stuffiness may rebound if you use them for more than three days. (See our Choosing Wisely guide on treating sinus problems.)

See the doctor. If symptoms worsen, if symptoms last longer than 10 days without improving (most cases resolve on their own in that time), or if you experience severe pain around your nose and eyes, a fever above 102° F, or a hot, red, fast-spreading rash.

Keep in mind. You usually won’t need antibiotics; most sinusitis is viral, and antibiotics work only against bacteria. Using antibiotics unnecessarily can lead to bacteria that are immune to those drugs, and antibiotics can have unpleasant side effects, such as diarrhea. 

Norovirus

Commonly but mistakenly called stomach flu, norovirus causes vomiting, diarrhea, stomach pain, and sometimes a fever. It usually runs its course in 48 to 72 hours.

Avoid it About half of people who come into contact with someone with norovirus contract the illness themselves, so be careful around anyone who is vomiting or has diarrhea. Wash your hands often, especially after using a toilet and before eating or cooking. If you're not able to wash your hands, use hand sanitizer with at least 60 percent alcohol.

If you think you have it Rest, and because you’ll probably lose a lot of fluids, be sure to sip plenty of water, fruit juice, broth, and other caffeine-free, nonalcoholic fluids (a little at a time, if that's all you can manage). And if your urine is dark, you may be dehydrated and need to increase fluids.

See the doctor If you’re extremely thirsty, confused, dizzy, unsteady, or faint, or urinating less than normal. These may be signs of severe dehydration. 

Keep in mind Norovirus is highly contagious. Stay home while you’re ill, and afterward, disinfect surfaces you touched with a bleach-based household cleaner.

Bronchitis

The main sign of bronchitis, which occurs when the tubes that carry air to your lungs become inflamed and produce excess mucus, is a cough that can linger for up to three weeks. Normally the cough generates mucus in the first three to seven days, and becomes dry after that. 

Avoid it Bronchitis is usually caused by common viral infections such as cold and flu, so practice healthy lifestyle steps like those suggested above for preventing sinusitis and get an annual flu shot. And avoid people who are coughing or sneezing. 

If you think you have it To soothe an irritated throat and loosen mucus, breathe steam from a shower or kettle or suck on a throat lozenge. Remember, though, some coughing is useful because it can help you get rid of bacteria that can cause a secondary infection such as pneumonia (see more on pneumonia below). 

See a doctor If symptoms ease but then worsen again—you have a new fever or chest pain, for example, or cough up blood. 

Keep in mind Antibiotics will almost never help cure bronchitis or prevent it from turning into pneumonia. But doctors still commonly prescribe those medications for bronchitis. If that happens, tell your doctor, "I have a cough. I’m a little worried about it, but I only want to take an antibiotic if it’s really necessary," suggests Jeffrey Linder, M.D., associate physician at Boston’s Brigham and Women’s Hospital.

Pneumonia: Viral or Bacterial?

Is pneumonia one of the common viral infections to watch out for this winter? This infection of the lungs may be caused by a virus, but it's more commonly caused by a bacteria called pneumococcus. You can be vaccinated against this bacteria, and the Centers for Disease Control and Prevention recommends vaccination for older adults, young children, and people with certain risk factors or conditions, such as those that signal a compromised immune system (like chronic renal failure, HIV, and cancers such as leukemia, lymphoma, and Hodgkin disease).

Symptoms of pneumonia can include a cough; greenish, yellow, or blood-tinged mucus; a fever that may be high; shortness of breath, pain when breathing or coughing; chills; headache; and even nausea, vomiting, and diarrhea. Symptoms may occur after you're starting to feel better from an earlier upper respiratory infection.

See your doctor as soon as you suspect you have pneumonia because the condition can range in severity from mild to life-threatening. If you're found to have pneumonia, your doctor will prescribe antibiotics. In some cases, you may need to be hospitalized while you're treated.