We have four pairs of sinuses — empty cavities that serve to lighten the skull (see Diagram — Upper Respiratory Tract). Even though viruses can infect them, when we say “sinusitis,” we refer to bacteria (see Differences Among Germs), which enter through openings from the nasal passages. Bacteria are more dangerous, because they can spread from sinuses to the eye or brain. But that’s uncommon, and they can be cured with antibiotics.
Symptoms of Sinusitis can be any combination of runny nose, cough, or facial pain (or headache in the front of the head). Most people who complain their “sinuses are acting up” don’t have bacterial sinusitis — they have Allergic Rhinitis (Hay Fever). They will get relief with allergy medicines, not with antibiotics. Unfortunately, when patients suggest they need antibiotics (or demand them), clinicians often keep them happy & move on to the next patient. That’s quicker, easier, & good for business; but it causes more drug-resistant bacteria, which is real bad in the long run.
Acute Sinusitis is a hard diagnosis. X-rays are often inaccurate, and CT scans have many false-positives. One good clue to Acute Sinusitis is “double-worsening” — a common cold begins, seems to be getting better, & then the patient gets sicker, with more nasal symptoms. If one side of the face hurts more than the other, or if it hurts to tap the upper teeth on one side but not the other (& not just one tooth), we’re surer of our diagnosis. Fever for more than the first 1-2 days of a cold also suggests bacterial infection.
Chronic Sinusitis is also hard to identify. We diagnose it when it seems like a patient seems to have recurrent allergies, but allergy medicines don’t help. CT scans can then be useful. The problem with chronic sinusitis is that treatment involves long courses of antibiotics, often combined with steroids. Neither of those are healthy, but may be necessary, so we really want to be sure of the diagnosis. Ear-Nose-and-Throat (ENT) specialists can examine the nose with special equipment (endoscopy of the nose), which is helpful, especially in younger persons for whom we like to avoid the radiation of CT scans.