A. First, see if you can figure out why she's doing this -- it's usually out of habit or to relieve an itch. Look for a physical cause first: If she suffers from nasal allergies -- especially to dust or pollens -- she may pick her nose because it's irritated. Obvious signs that her picking is allergy-related: a frequent runny nose, watery eyes, and sniffing. If she mainly does this during the winter, dry air could be to blame; spritzing a couple of drops of saltwater nasal spray a few times a day will help keep her nose moist.
If you've eliminated these causes, her nose picking is most likely just a habit. While it's generally harmless, it can cause nosebleeds. Plus, the nose is a main entry for germs, and since pickers may also be eye rubbers, they're more likely to transfer germs to the eyes, which could result in conjunctivitis, an annoying infection.
In my experience, kids tend to outgrow the habit -- it's most common among 2- to 5-year-olds. By kindergarten, social consciousness kicks in and nose picking is on the way out.
But if you can't bear to wait that long, try explaining how picking the inside of the nose can make it bleed. I find that when kids know what causes boo-boos, they'll usually avoid that activity. Two- and 3-year-olds, however, may not be old enough to understand, so breaking their pattern is tougher. Instead, see if there's a relationship between nose picking and boredom or anxiety. When you see her reach for her nose, you should say something like "Let's go outside" or "Let's sing a song." The goal is to divert her attention. Or try getting your daughter to substitute a less offensive alternative: Show her how to rub her fingertip around her nose instead of picking it.