Would it be foolish to go to a&e for an infected wisdom tooth?

Infected wisdomteeth: I am not sure what a&e is, maybe I am getting a little bleary eyed, but i can tell you this if you have infected wisdom teeth you need to see your dentist as soon as possible to either have the infection treated or the wisdom tooth removed. Infections can spread and can get into the bloodstream and cause more serious problems, at the very least get on some antibiotic asap and see the dentist a soo.

Not best place: If by "a;e" you mean accident and emergency, that's not the best place. Best place is office of an oral surgeon. Please go asap to limit spread of infection. Oral surgeons are staffed, equipped, and best qualified to resolve your problem. Emergency rooms simply are not.

Need dentist/os: You really need to see an oral surgeon. Going to emergency would be one additional step where they may end up referring you anyway.

Infected tooth: Going to an emergency medical facility would only be a good idea if it's a holiday, or after normal business hour situation when there are no dentists available to see and treat you. This is especially true if you have trouble breathing or swallowing, the swelling is rapidly increasing in size or you have unbearable pain and no otc pain medication is helping. Otherwise see an oral surgeon today.