Cat suddenly allergic after anesthesia?

Hi. I have a 5 years old cat who had her first dental cleaning last summer. She had rough couple days recovering from the anesthesia but she recovered. She did start scratching her chin afterwards tho. She ended up getting a pink blad patch under her chin for a week or so, went away but she still scratches her chin/ears/lips. The itchiness seems to come and go but I've just found another pinkish red spot just above the corner of her lips . She's never had this kind of issue before and the two vets she's met since her itchiness are suggesting food allergy. Has anyone heard of sudden development of food allergies after dental cleaning or anesthesia?

Welcome to TCS! Must be so frustrating to be dealing with a new skin condition.

I can in theory see how the introduction of a new substance into her system could trigger a form of inflammation and thus an allergy. Have you talked to the vet who did the dental work? I wonder if maybe some tube or something was in direct contact with that area causing the allergic reaction? 

Have there been any changes in diet recently?

Thank you.
Not much change in diet and the itchy spots seem to be moving around her face/head area.

Allergies can appear for no apparent reason. Stress from the vet visit is just as likely to be a trigger. Try Acana cat food for a while. If she is reacting to additives or grain this will stop the allergy.

Well, they do say sometimes people come out of being anesthesia different. Personality changes, cognitive changes, etc. Maybe it can happen with animals, too? I know that's not a helpful reply but it's an interesting thing to consider definitely.

@vhsjl....I am also wondering if your Vet did an X-ray, before or after the dental cleaning, to check the roots of the teeth.

Sometimes Vets will not do x-rays, because of the added costs, but then they may miss underlying root problems, that can also cause pain and itching under the chin of a cat.

I would ask your Vet, just to make sure, if dental roots can be a cause.