Having itchy palms because of an allergy might happen commonly in terms of a large population, but it is not common to have this condition. If it happens to you then you should get it looked at instead of biting them. This is the correct and acceptable response. Putting your hands in your mouth and using your teeth because something is wrong with your palms does not need to be normalized.

If people have itchy palms for any reason, I’m not shaming them. I’m pointing out that putting your hands in your mouth is strange.