Spider nevus is mainly distributed in the upper body, within the distribution of superior vena cava in the face, neck, forehead, back of hand, upper arm and shoulder, etc. Severe spider nevus can be seen all over the body. Spider nevus is a vascular nevus formed by the expansion of the terminal branches of small arteries on the skin surface, also known as spider capillary dilation, which is clinically seen in liver lesions such as viral hepatitis and cirrhosis. The liver is one of the organs that metabolize estrogen. When the liver is continuously damaged, the synthesis and detoxification functions of the liver become abnormal, resulting in a decrease in estrogen inactivation in the liver. Abnormally high estrogen levels in the body can cause small blood vessels to dilate, which can lead to spider nevus. It appears as one or more red nevi on the skin with a raised center and many capillaries extending around it in a diffuse manner, resembling a spider’s leg, which can fade when pressure is applied around the center and turn red again after pressure is removed. In addition, because spider nevi are affected by hormones, they can occur not only in patients with liver disease, but also in normal people, such as women who are pregnant for 2-5 months, taking estrogen drugs, menstruating and menopausal, etc. Because estrogen in the body is in excess, spider nevi can also appear, and usually they can disappear gradually with the gradual reduction of estrogen a few months after stopping drugs or giving birth, so they need to be differentiated. In addition, in addition to spider nevus, patients with liver disease may also have other accompanying symptoms, such as weakness, loss of appetite, and yellow skin staining, and spider nevus will gradually increase and become larger as the disease progresses. At this time, patients should seek medical examination of liver biochemistry, abdominal ultrasound and other items to clarify the cause of liver damage and the degree of liver damage, and take targeted treatment to prevent disease progression.