The appearance of small red spots like blood spots on the breasts may be related to allergic reactions, or may be caused by allergic purpura, senile hemangioma and other reasons. 1. Allergic reaction: Especially for those who are allergic themselves, after just replacing the new underwear, if they are allergic to the material of the underwear, it may cause an allergic reaction to the local skin of the breasts, which will result in the appearance of small red dots like blood dots on the breasts. 2. Henoch purpura: this disease is usually due to autoimmune system dysfunction, caused by a kind of allergic inflammatory reaction, can involve more parts of the body of the small blood vessels, which may cause the breast area appeared small red spots, like blood spots. However, purpura hemorrhagica is distributed throughout the body. It does not simply appear in the breast. 3. Elderly hemangioma: it is mostly considered that it may be caused by the proliferation of capillaries in the dermis, which may lead to the appearance of small red dots like blood spots on the local skin, which may cause the appearance of small red dots like blood spots on the breasts and is not accompanied by itching and pain symptoms. At the same time, it may also be seen in folliculitis, spider nevus and other conditions. The appearance of small red dots like blood spots on the breasts may also be caused by other reasons, if accompanied by other obvious discomfort, you should consult a doctor as soon as possible to diagnose the cause, and then give targeted treatment.