I have this problem since last 10-15 days which is slowly getting worse,and the trouble is

i get severe itching,on my legs,esp on the calf muscles,knees and butts.I dont see any other symptom,ie my skin
looks normal.It is after itching, that it gets red.I dont think it is allergy,or dry skin.
I am otherwise healthy 26 yr old female with no other known problem.