Dear Dr. SerVaas: When my stepson was six or seven years old, he suffered lactose intolerance when he had head colds. As did many children at that age, he would often sniff the mucus into his throat rather than blow his nose. Also, I am sure he swallowed mucus while sleeping.At these times, he could not consume dairy products without experiencing cramping and vomiting.

We gave him lactose-free milk substitute until the infection ran its course (a week or two). Then, after we tested with a small amount to be sure, he would be tolerant of dairy foods once again. Are you aware of others with this condition?

Dwight Lamb
Indianapolis, Indiana

Dear Reader: Very good research on your part. I hope this will help parents encourage their children to blow their mucus into a tissue. We're passing your observation on to the editors of Jack & Jill and Humpty Dumpty's magazines. Readers, please share any similar case histories.