4 Sneaky Signs a Sinus Infection Is Brewing

You can't breathe, your nose is running, and you feel lousy. Sounds like a cold, right?

Well, it can be—but not so fast. What you think is a cold might actually be a sinus infection. Sinus infections can be sneaky, so people tend to confuse them with a cold or other illness. Part of the problem is that not everyone knows all the subtle ways they can rear their snot-filled heads (Here are 7 signs your cold is actually something worse).

Your sinuses are the cavities that drain into your nose. A sinus infection pops up when a virus, bacteria, or (rarely) fungus gets into the lining of one or more sinuses, says Richard Nass, M.D., a sinus specialist in New York City and clinical associate professor of otolaryngology – Head and Neck Surgery at the New York University School of Medicine.

Another reason people often mistake a sinus infection for a cold is because a sinus infection often pops up after a cold. That's because those linings of your sinuses are more vulnerable to infection after a cold, since your sinus openings tend to swell, adds Eric T. Waterman M.D., an otolaryngologist and facial plastic surgeon in private practice in the Seattle area.

But while colds typically go away within five days, anything that lasts longer than 10 days is more likely a sinus infection. Sinus infections are either acute (lasting around four weeks), subacute (four to 12 weeks), or chronic (12 weeks or more), says Dr. Nass. A chronic infection can occur when an acute or subacute one goes untreated, says Dr. Waterman, and the symptoms are subtler but can lead to fatigue over time, so they’re worth treating.

Here are a few signs you’re dealing with a sinus infection instead of a run-of-the-mill cold.