After celebrating the end of P-1 year, I came home at 1:30 am, tired and with some strange rash on my right forearm. I am sure I haven't touched any suspicious objects or yellow flowers (I am allergic to yellow flowers - but then my arm would be all red and swolle). I had a hepatitis B booster shot yesterday in that arm. And held a strawberry daiquiri. But food allergies have different symptoms, while a reaction to a vaccine component would start at the place of the shot.I can't be allergic to cats, because they my both arms would be covered with the rash. I just put some hydrocortisone on it and went to sleep. At least it doesn't itch.