The red stripe on the inner thigh is an atrophic stripe. Atrophic lines are due to the degeneration and fragility of skin elastic fibers, which break after overstretching and appear as wavy stripes of atrophy on the skin. There are many causes of atrophic striae: 1. pregnancy. 2. sudden weight gain or rapid growth is also a common cause of this disease, mostly seen in adolescent men and women. 3. glucocorticoid steroids can inhibit fibroblasts and break down elastin, causing degeneration of elastic fibers, so patients with Cushing’s disease, long-term corticosteroid use or topical corticosteroid use are also prone to atrophic striae. There is no special method to treat atrophic lines, you can apply olive oil on the affected area.