Talk to Dermatologist on Skin Problem

Respected all doctors, I have Red spots on the skin especially on legs. it's been 4 years this is happening every winters (not in summers). nothing like scratching or pain but now it's little bit burning sensation. I consulted a doctor, he gave me medicine which resulted in constipation and feels like I'm gonna throw everything that I've eaten but nothing happened like that. But after 3 to 4 days my waste or poop was light red in color. it was 2 times a day and then I skipped medicine and then it was normal. But next day it happened again. To whom I should get examined.