Tell Me Why I Sneeze
The Kid's Answer
Jaleesa (left), age 4: Because my nose gets tickly.
The Parent's Answer
Claudio, Jaleesa's dad (left): Allergies make you sneeze. You could be smelling flowers; if you're allergic, you'll sneeze.
The Scientist's Answer
"Sneezing is an important reflex that protects us from things in our environment," says Richard Wasserman, M.D., Ph.D., a physician and spokesman for the American Academy of Allergy, Asthma, and Immunology.
Just about anything can trigger a sneeze, Dr. Wasserman says. Common irritants include pepper, dust, chemical odors, cold viruses, and allergens such as pet dander and plant pollen. When any of these things tickle the mucous membrane inside your nose, nerve endings embedded there send a signal to your brain stem.
The brain then rallies the muscles in your body that coordinate to generate a sneeze. Those muscles — in the abdomen, diaphragm, chest, throat, and face — work together, causing you to take a sharp, inward breath and then expel it through your nose.
How to Explain It to Kids
A sneeze is like a cough in your nose. It's your body's way of getting rid of germs, dust, and other potentially dangerous things. The air we breathe is full of stuff like that. We can't see it, but the nose knows.
When your nose senses that it is being invaded, it sends a message to your brain: "Alert! Alert! Something has gotten in here that doesn't belong!" Your brain gets your muscles working, filling your lungs with a deep breath and flushing the bad stuff out with a sneeze. A good one can whip through your nose like a mini-hurricane, reaching speeds of 100 miles per hour.