What Causes Syncope With Leg Redness And Blotching?

i am a 23 year old female ,ive always had a problem with fainting and ive had twins who are 2 years old and the problems started when i was pregnant and still are now,when i stand my legs are red and blotchy and sometimes purple i also get a red patch on different parts of my body with skin contact and clothes contact it heats up to the point that it melts creams off my skin.