Your pediatrician should be able to do bloodwork to find out if there is a deficiency. My son had started to chew on things, lick windows, etc... His pediatrician ran bloodwork to rule out it being a deficiency just in case. It turned out his was being caused by his B12 being to high but deficiencies can cause it as well.

Our son had an issue of chewing on things when he was in elementary school-it turned out to be more of a sensory stim for him. He would switch from one thing to another, straws to pencils. He has naturally decreased this over time but he still stims in the form of flapping or occasional vocalizations.

My son is just starting to stop chewing on things. We have a collection of chewies for that...look up chewies for kids...they even have chewy necklaces and chewy scarfs for the everyday clothes chewer:)

My son did that. I tried giving therapeutic chews as a replacement. Rulers that are also therapeutic chews, so on. He seems to have outgrown it, or maybe we have found the meds that work best for him. I'm not sure. But He used to chew holes in all of the necks sleeves etc. He is 20 now. He is still has to be reminded to not use his clothing as his napkins, tissues, and so on but his is a lot better now that he is older and he no longer chews on his clothing and no longer needs the chews. You can find them on Amazon for a pretty reasonable price.

My grandson has PICA. It started out that he was eating the fuzzy's from his blanket. Now he is eating anything that he can get his hands on. Plastic, wood like from books and puzzles. He like to pull threads from clothing and towels and eat that. Just keep and eye on him and try to stop the eating before it gets to his mouth. It's very frustrating. He does not have any kind of deficiencies.