Do you suffer from a undiagnosed health condition?

Well a few years ago I started suffering from an irritating condition.... I just feel a terrible itch and all that I want to do is blowing my top off and scratching my back. I have asked my doctor who did some blood tests and said that I am healthy and it might be some kind of allergy and there is nothing much you can do about it. Allergies are tricky to diagnose he said. I am suffering this condition during the change of weather... it always starts late April or beginning of June. When it happens I just take a cold shower and change my clothes and try to relax as much as possible.