Sometimes allergies are VERY hard to diagnose because it may be a combination of things that set it off. Say it is raining, you eat ice cream and you shaved the night before... all those three things would have to be present (I'm NOT saying that is known to cause an allergic reaction, I'm just saying that it could be a combo of things and you really have to write down EVERYTHING and see if there's any corrolation somewhere. Then even if you DO write it down, you may be missing something like suppose you eat ice cream, you shave and you put your hand on your face after touching metal... you can't possible write down EVERYTHING you do, and it may be impossible to tell WHAT is giving you the allergic reaction.