Q: What is the significance of the color of the discharge from a child's nose? Is yellow or green worse than clear?
A: Nothing that runs from a child's nose is very pretty to look at, but to the doctor's eye the color may be a message about the cause of the drainage.
Early in their course, virus infections of the respiratory tract cause the tissues which line it (mucosa) to produce a clear, water mucous which runs out of the nose, and down the throat, too, for that matter. Clear mucous often means a viral infection, like the common cold.
More serious viral infections, like influenza and the measles, also cause nasal discharge. These can cause a large amount of somewhat thick mucous discharge. As viral infections progress, the nasal discharge may become thicker and less transparent, even tinged with yellow. Often, the child is already getting well when this happens. Nothing needs to be done if the runny nose gradually clears up.
On the other hand, a yellow or green nasal discharge makes a doctor think of pus, which is usually caused by bacterial infection.
Bacterial infection of the sinuses (which drain into the nose) or of the nose itself, is called sinusitis. This is not common in infants because they have not yet developed a full set of sinuses.
Persistent green or yellow discharge, especially if it is from one nostril only and is very foul smelling or is tinged with blood, makes doctors search for a foreign body -- some small object the child has stuck up the nose.
Finally, the children who are experiencing allergic symptoms or irritation or their nose and throat by poor air quality -- cigarette smoke, for example -- may have runny nose. Usually the mucous is clear to slightly opaque, but not colorful in the absence of secondary bacterial infection. In summary, if your child has long-lasting nasal rainbow, call your doctor!
Dr. Wilson is director of pediatric primary care of the Johns Hopkins Children's Center; Dr. Joffe is director of adolescent medicine.