Many pinpoint red spots on the arm of hepatitis B are mostly considered to be caused by spider nevi, subcutaneous bleeding, and skin diseases. 1. Spider nevus: the appearance of spider nevus on the body of hepatitis B patients is mainly a symptom manifested due to the decline of liver function. Spider nevus can be distributed in the neck, face, arm, forehead, back of hand and other parts of the body. Pressing the center of spider nevus will make it disappear immediately, and this state can determine whether it is a spider nevus or not. 2. Subcutaneous bleeding: Hepatitis B patients are mainly due to chronic infectious diseases caused by hepatitis B virus infection, patients in the disease progression of liver function damage aggravation, when the blood function is abnormal, platelets or coagulation mechanism is reduced, naturally induced local capillary breakage, which leads to subcutaneous bleeding, the formation of red blood spots. 3. Skin diseases: Hepatitis B patients with pinpoint red spots on the body, may not be caused by hepatitis B, can not be ruled out as a result of skin diseases. For example, allergic dermatitis, viral infections and other related skin diseases can also induce this symptom. Hepatitis B arm a lot of pinpoint red dots, should be highly attention, timely go to the local hospital, as soon as possible to find the problem as soon as possible control.