I have been scratching my legs because they felt really dry, but when I looked down after awhile I noticed that my legs had dark splotches all over them.  Im not sure if I scratched so much that I created these splotches or if the splotches themselves are why my legs itch.  The splotches themselves dont itch, but the entire leg does.
Hi, you are having necrosis of legs, i.e. Chat Doctor.  You are having severe itching. Blotchy patches may be ecchymosis due to severe scratching. Rule out anemia, DM, thyroid dysfunction or other internal diseases by blood testing. Apply emollient containing liquid paraffin or lactic acid. Take antihistamines. If required, short course of steroid may be taken in tampering manner. Avoid soap bath. Take treatment for any internal disease if it is there. Do not worry, be calm, you will be benefitted. Ok. If needed, consult dermatologist.