Q: My six-year-old son always cracks his knuckles. Can this be harmful?
A: Many children like cracking their knuckles because of the funny noise it makes, the looser feeling the joint has after the cracking, and stress relief. There is no evidence that cracking causes arthritis. However, the ligaments around the joint can be temporarily injured. I suppose cracking over years can lead to slightly larger knuckles. As with most habits, it persists because it relieves stress or because of the reaction (positive or negative) it gets. I would start with ignoring, and then go to behaviour modification. After telling your son you want him to stop, praise him when he doesn’t do it.
Finally, if he’s doing it because he’s anxious, get to the bottom of that issue. Even in a six-year-old, anxieties not addressed can become worse.