While they do look like hives, in the sense they are raised bumps on the skin, I have never seen hives in such a regular linear pattern. That's the only thing that makes me think it could be something else....I'm honestly no expert and hives seems very logical however.
It does seem that it could be caused by your shampoo however and I would consider switching to something else. Your vet honestly has no clue about hives or allergic reactions? That seems hard to believe. Posted via Mobile Device