Recently I Have Been Having Bouts Of Itchiness Of Skin

Recently I have been having bouts of itchiness of skin in different areas, such as abdomen (top left), shoulders, underarms, lets. My concern is when the itch occurs it is insatiable and when I scratch it feels like my skin is burning and later there is a very large looking bruise. The largest and most recent is on my upper left abdomen area. It is warm to the touch but not painful. Is this a normal way of bruising? I didn't hit it or anything.