What Causes Bleeding Under From Leg After Standing For Long?

Hi when I stand on my feet for 6-8 hrs my legs break out and looks like I have bleeding under the skin. Started about a year and half ago. Was from the feet and slowly up to my stomach now. Went to doctor then was sent to hematologist. All blood work came back okay. Doctor says I have Nonthrombocytopenic purpura but my concern is it keeps coming back!!!!!!! Is it okay for my legs to bleed that much under the skin so often?