The purplish red stripes on the inner thighs are clinically called swelling or atrophy stripes, which are related to the sudden increase in local tension of the thigh skin, and occur during adolescence, caused by the sudden growth of the body or weight gain and obesity. Some patients may also be related to the use of corticosteroids or a sudden increase in corticosteroid secretion, such drugs or hormones can cause the dissolution of elastin, elastin dissolution, fracture after the clinical symptoms, mainly manifested in the inner thigh longitudinal row of purple-red wavy stripes, can be several parallel to each other, the color gradually becomes lighter, into a small wrinkles, similar to Stretch marks on the abdomen of pregnant women. Pregnant women usually have no conscious symptoms, and most of them can be relieved by themselves without treatment.