Q. This will probably sound picky coming from a kindergarten teacher, but I've got to know: Why don't children blow their noses?

A: Nose-blowing appears to be largely a social skill, and a rather advanced one at that.

There are many parts to a good, nose-cleaning blow, from finding a tissue or handkerchief to the final wipe. Directing a forceful breath through the nose is particularly complicated. Even after children have the planning and motor capabilities to carry out each step of the task, they are unlikely to make the effort. After all, they would be doing so only to avoid annoying others.

Kindergartners see themselves as the center of the universe. If they are troubled by nasal mucous, they sniff and swallow.

Actually, pediatricians might advise against nose-blowing. Many think the pressure of blowing with the nose pinched drives mucous into the middle ear, setting up the possibility of an ear infection. Besides, children have so many runny noses the first few years of school, complete and frequent blowing would leave little time for instruction!

Dr. Wilson is director of general pediatrics at the Johns Hopkins Children's Center; Dr. Joffe is director of adolescent medicine.