Would the doctor make a contribution me an antihistamine shot for a reckless that not a soul seem to know what started it?

Would the doctor make a contribution me an antihistamine shot for a reckless that not a soul seem to know what started it?
Best person to ask would be your doctor. He may bequeath you a shot, or another type of antidote (such as a topical cream). Once he looks at it, he'll be better able to determine whether it's a over-hasty, hives or something else.
The source of a rash may be rugged to determine if you don't have a hisotry of allergic reaction, or can't recall coming into contact beside a likely impose.
But the antihistamine shot is to take assistance of the symptoms. You do want to rash to walk away, right? If you are no longer exposed to the source, this should be the end of it.
Now, if the shot doesn't give a hand, it may not be due to an allergy. But your doctor probably based the diagnosis of allergy induced reckless by the presentation, location, and your history.