Stretch mark like rash on skin... what could cause it? treatment?

Stretch Mark Therapy: Tretinoin creams such as Retin-A and Renova (tretinoin) are helpful. These creams are only effective on very new stretch marks and must be administered in less than six weeks after their appearance and while the mark is still red or pink.Pulsed dye laser therapy can stimulate the growth of elastin and collagen in our skin. This method works best on new stretch marks but can be useful on old marks as well.