A lot of blood spots on the forehead and arms are usually symptoms of cherry angioma, spider nevus or thrombocytopenic purpura. 1. Cherry-like hemangioma, the etiology of which is not completely clear at present, is caused by abnormal proliferation of capillaries and is related to the decline of skin function. The main manifestation is the appearance of scattered red translucent papules or nodules on the skin, mostly burgundy or bright red, with smooth surface, usually without obvious discomfort. 2. Spider nevus is caused by abnormal metabolism of estrogen and progesterone leading to capillary dilatation, which is commonly seen in patients with liver diseases, pregnant and lactating women, and can also appear in normal people. The main manifestation is the appearance of red spots on the skin from the tail of a needle to the size of a grain of corn, and the red spots are surrounded by spider leg-like pseudopods. 3. Thrombocytopenic purpura is caused by a decrease in the number of platelets in the blood, and is related to a variety of factors such as heredity, immune system disorders, etc., and the cause of the disease is not completely clear at present. The main manifestation is the appearance of subcutaneous blood spots on the skin and oral mucosa of the body, the blood spots do not fade when pressed, and the rash has no obvious discomfort. It is often accompanied by symptoms of bleeding gums, menorrhagia and even retinal bleeding. There may be other reasons why there are many blood spots on the forehead and arms, so it is important to go to the hospital in time to find out the cause and treat the symptoms.