What Causes Itching At Night And Dizziness?

HI, my dad has this itching (not severe but definitely more than just a simple itch) at night only and none in the daytime and he has dizziness too. He went to the doctor but they just don't believe him because he has nothing to show as the itching occurs only at night. He doesn't know about his sugar level though. I would be glad if you could explain this. Thank you