Scratch it if you must. If it keeps happening, put some lotion on it because it could be dry skin. If it keeps going on, then you could be having an allergic reaction to something. Maybe not...but if...
It doesn't mean anything unless it itches allot and it won't stop. If that happens run to the store and get some Aveeno anti-itch body lotion and then go to see the doctor. Apply the anti-itch body...