Limb ulcers are an important complication of systemic scleroderma, and persistent and recurrent ulcers can cause severe pain, infection, gangrene, functional impairment, and decreased quality of life, causing great suffering to patients. Because of this, the study of scleroderma extremity ulcers has become a hot issue for research in recent years. The main pathological changes of SSc are inflammatory cell infiltration of connective tissue, intimal hyperplasia, vascular occlusion, fibrous tissue proliferation and sclerotic atrophy. In the initial stage of skin lesions (inflammatory phase), interstitial edema of the dermis, separation of collagen fibers, perivascular lymphocytic infiltration of small vessels, edema of the vessel wall, and breakage of elastic fibers. Thereafter, the perivascular inflammatory cell infiltrate subsides, collagen swells, and acidic mucopolysaccharides and their collagen increase around the small vessel fibers. In the later stage (sclerotic phase), collagen fibers homogenize, collagen fiber bundles parallel to the epidermis increase, and collagen fibers proliferate and extend deeper. Small vessel walls thicken and the lumen becomes smaller to the point of occlusion. Late changes continue to occur, leading to epidermal and appendage atrophy, calcium salt deposition, and sclerotic atrophy of fascial muscles. Symptom examination: Early swelling of the hands and fingers may also involve the forearms, feet, lower extremities and face, but the lower extremities are less commonly involved. The period of swelling may last for weeks, months, or even longer. The edema is concave or nonconcave and may be accompanied by erythema. The skin lesions begin at the distal end of the limb and progress to the proximal end. The skin gradually hardens, thickens, and finally adheres to the subcutaneous tissue (sclerotic phase). Extremity ulcers can be clinically divided into three phases: Phase I (local ischemic phase): coldness, coldness, numbness, and mild pain in the unterminus of the lesioned limb. The patient walks a certain distance with soreness and pain in the plantar or calf muscles, is forced to stop walking, and can walk after resting for 3-5 minutes to relieve the pain, and pain occurs again after walking the same distance, with pale skin color and low skin temperature at the toes (fingers). The pulsation of the uncinate artery is weakened or disappears. Stage II (dystrophic phase): coldness, coldness, numbness, pain and intermittent claudication of the affected limb, etc. The symptoms of stage I are aggravated, with rest pain, severe pain at night, sitting on the foot and having difficulty sleeping at night. The skin of the foot is nutritionally impaired epidermis pale, flushed, purple or cyanotic, foot sweat reduced or no sweat, dry and flaky skin, atrophy, reduced elasticity, sweat hair loss, sparse, often with calf muscle atrophy. Stage III (gangrene phase): Due to severe ischemia of the diseased limb, ulceration or gangrene occurs at the extremity, often starting from the toe and gradually spreading upward, gangrene is dry or wet, mostly confined to the toe or foot, but can also involve the ankle or calf, the back of the foot alone or heel ulceration gangrene combined with infection, limb ulceration, may have a foul odor, pain or no pain, long-lasting treatment.