Varicose veins are tortuous, dilated veins caused by blood stagnation and weakness in the walls of the veins. Varicose veins can occur in many parts of the body, for example, hemorrhoids are actually a type of varicose vein, and varicose veins occur most often in the lower extremities. It is worth emphasizing that varicose veins themselves may be a secondary manifestation of other pathologies, therefore, a clear diagnosis and differentiation should be made for patients presenting with varicose veins and active management of the primary pathology. So, what are the common clinical conditions in which varicose veins of the lower extremities can appear? 1.Primary lower limb deep vein valve insufficiency: the symptoms include lower limb superficial varicose veins, swollen calves, swelling and discomfort of the limbs, aggravated after standing or exertion, and reduced after rest, and then pigmentation and ulcers appear after a long time. 2.Simple saphenous vein insufficiency: it can be seen that the superficial veins along the inner side of the lower limb are tortuous and dilated, but there is no obvious discomfort. 3.Transportation branch vein insufficiency: varicose veins of lower limbs are not obvious, but there is often obvious pigmentation in and around the transportation branch area, accompanied by skin itching and even ulcers. 4.Post-deep vein thrombosis syndrome of lower limbs: It is secondary varicose veins of lower limbs, mainly in the veins of lower leg branches, with heavy, swollen and painful limbs, and obvious swelling of affected limbs, which is aggravated after activity or standing, and cannot be completely relieved after bed rest. The skin becomes thin and hyperpigmented. 5, lower limb arteriovenous fistula: varicose veins in the lower limbs, accompanied by increased skin temperature, tremor and murmur in the varicose veins near the fistula. The possibility of this disease should be considered in young people and children with growth, thickening, hairiness and sweating of the affected limbs. 6, venous malformation bone hypertrophy syndrome: this disease has significant limb growth, thickening, superficial veins abnormally thick and varicose, skin hemangioma (wine-colored spots) triad, lower limb venography can be found in the deep venous malformation is partially absent, branching disorder and more, superficial varicose veins, etc. 7.Buga syndrome: manifested as hepatosplenomegaly, ascites, esophageal varices with thoracoabdominal wall varices, bilateral lower limb edema and varices, skin pigmentation, ulcers, etc. 8, iliac vein compression syndrome (Cockett): also known as May- Thurner syndrome, mainly refers to the left common iliac vein at the confluence into the inferior vena cava by the long-term compression of the right iliac artery from the front across and the mechanical effect of its pulsation, resulting in changes such as intimal hypertrophy, luminal adhesion, luminal narrowing or occlusion of the left common iliac vein, which in turn causes obstruction of iliac venous return. The pelvic and lower extremity venous reflux is impaired, resulting in a series of clinical symptoms and syndromes. It is common to see varicose veins in the lower extremities, edema, and in severe cases, hyperpigmentation and even ulcers. These are the most common diseases that cause varicose veins in the lower limbs, so when you have varicose veins, you must first clarify what kind of cause it is, and treat the varicose veins along with their causes, so that you can be thorough and achieve the ideal treatment effect and reduce recurrence.