Small red dots on the arms and body may be due to hemangioma, spider nevus, purpura, periosteal keratosis, and so on. 1. Hemangioma: cherry hemangioma is a manifestation of skin aging caused by sun exposure, with the appearance of small red dots of needle tip to rice grain size, which can appear on the arm or other parts of the body, will not fade for a long time, and will not fade when pressed. 2. Spider nevus: It is caused by the expansion of capillaries under the skin, and the color can be faded for a short period of time, and can be restored by removing the pressure. Mainly due to excessive estrogen in the body, can be seen in pregnancy and other physiological conditions, can also be seen in hepatitis, cirrhosis and other pathological conditions, it is recommended to improve the liver function tests. 3. Purpura: It is a bleeding spot under the dermis that does not fade when pressed, and may be related to thrombocytopenia and poor coagulation. It may be manifested as small red spots on the arms and body. 4. Periosteal keratosis: mainly distributed in the extension of the arm, the upper arm is more frequent, the localization can appear dense rough red or brown small red dots, mainly related to genetic factors. Patients who find their arms and body long red dots need to be timely to the hospital dermatology, follow the doctor’s instructions to carry out the appropriate examination to clarify the cause of the disease, and actively carry out the treatment.