hi, i have these red lines which keep appearing on my abdomen. they are red, and range from 1cm wide to an inch wide and about 5 inches long and run vertically, they are not stretch marks. i am obese and have an underactive thyroid, but i feel there is an underlying condition as i seem to gain weight extremely easy and constantly come out in hives. i also had a gastric band which was so problematic that i could barely eat for 2 years as i even vomited soup, yet i still didnt lose weight