How to make a penicillin rash stop itching

Antihistamine: First thing to do is stop taking penicillin, can take benadryl or other antihistamines over the counter as directed, but if you are having trouble breathing or feel ill, bloated, or uncomfortable, you may have a life-threatening allergic reaction and you need to go to an emergency room or urgent care center to get a shot of epinephrine immediately !