Red dots on the body may be caused by cherry angioma, allergic purpura, periosteal keratosis and other reasons. 1. Cherry angioma: in most cases, it is due to the abnormal proliferation or expansion of skin capillaries, which causes the symptom of round or oval red papules, often appearing on the hands, feet, face, trunk and other parts of the body, which can be manifested as the symptom of body long red dots. 2. Anaphylactic purpura: It is mostly due to the increase in capillary fragility and permeability after exposure to certain allergenic substances, which leads to inflammation or bleeding in the skin, joints, intestines and other parts of the body, and then leads to the symptom of long red dots on the body. 3. Keratosis pilaris: mostly related to heredity, metabolic disorders, vitamin deficiency, often manifested as follicular keratotic papules on the skin, which can be reddish-brown, skin color, can also lead to the body long red dots. Causes of body long red dots more causes, may also be contact dermatitis, pitting psoriasis, etc., it is recommended to go to the hospital in time for examination and diagnosis, clear disease after giving formal treatment.