Itchy - first trimester?

Hi all, I am 10w. Since 9w I have been itchy... mostly on my thighs at night, but some days all over (collar bone, arms, face... back... it moves around). I'm not scratching myself raw because the itch does move - but general focus area is thighs, bum, knees/backs of knees. I've heard of itching due to stretching skin (but I'm not gaining weight yet), and have heard of colastitis - but was under the impression that was a risk only toward 3rd trimester. Is this a normal symptom or should I be seeing my Ob?