Cold secrets only noses know.

Sneezes and snfffles signal that a cold virus has done more than make a nose drip. Most likely, it has also affected the sinuses, says Jack M. Gwaltney Jr., a physician at the University of Virginia Health Sciences Center in Charlottesville.

Until now, most physicians thought sinus problems devel. oped in the aftermath of a cold, probably because of a secondary bacterial infection. But actually, the tiny passages connecting these internal cavities to the nose close off early ir the initial infection, he and his colleagues report in the Jan. 6 NEw ENGLAND JOURNAL OF MEDICINE. As with the runny nose sinus problems typically disappear in a few days.

To understand how to fight colds more effectively, the Virginia scientists used computed tomography (CT) to look deep into the nasal cavities of 31 young adults who had just developed cold symptoms. They also tested nasal function in these and 79 more people with colds.

With a cold, the nostril's shelf-like structures -- called turbinates - swell, Gwaltney observed. "They play a large part in giving the feeling of being stopped up," he says. In addition, infected noses tend to move mucus back to the throat more slowly than normal.

The results indicate that cold medicines should quickly destroy the virus and stop the inflammatory response that causes nasal passages to clog, leading to a cold's annoying symptoms. Gwaltney is seeking such treatments with the help of CT. "It's a good way to measure what's going on," he says.