how long does a allergic reaction rash last
A rash from an allergic reaction to medicine has a variable clinical course. Even after the offending drug is discontinued, it can take weeks or months for the drug reactions to disappear.The durarion for the rash to cease is related to the exposure time and the amount of drug the person was exposed to.add a comment.nswer by Antony (169). Allergic reactions to Medicine are tricky. We can't predict how long it will take,may be a week. Better you should consult a Physician and follow the instructions will solve this problem.