Itching problem

So I had a woman pick up a puppy last Saturday. The puppy and none of the othr littermates itched AT ALL while they were in our care. The puppies that went home that day got collars put on them for the first time and started itching because it was the first time they've ever worn collars. I told the lady before she left to just give her time to get used to the collar and she'll stop the itching. Well today she told me she was still itching a lot, and she put frontline on her and gave her 3 baths with two different shampoos to try and stop the itching. She is worried and asked me for advice. This has never been an issue with any of my pups, and I can't help but think she is may be overexaggerating a bit since before she picked her up I would get at least 3 emails a day from the time she was 4 weeks old with questions. Of course I was happy to answer them, but it was a bit much and she works at a vet office which really made it weird because she should have already known most of the questions she was asking me. Anyway off my litte rant LOL. I told her to take the collar off of her if she hasn't already, and to stop giving her baths because it may just be drying out her skin with 4 baths (including the one I gave her before she left) in a matter of almost a week. I also told her it may be a food allergy and to switch her onto a different food to see how she does. Anymore advice? She was eating Purina puppy chow at our house, and I believe she was trying to switch her over to Royal Canin

All my puppies scratch from new collars on them!!! Never had any other issues. Tell her to just take the collar off for a few days and give them some benedryl and leave well enough alone.....she is probably adding to the problem!!!

Yes that's what I told her. After discussing with her where she was itching, and if she had any dander, hair loss, or redness we think we found what the issue was....which was what I kept telling her all along LOL. She didn't have any dander, hair loss, or redness that would be typically associated with an allergy. She kept scratching around her head and collar area. I gave the puppies collars to go home with, and they were the kind with the holes in them for adjusting versus the snapping kind. She said the puppy kept biting at the extra slack I guess, but she just thought she was playing/teething. I told her to take the collar off for a few days or to try switching to one that clips, and adjusts on the actual collar....so we'll see if it does the trick.