Red blood spots on the skin may be caused by purpura, pigmented purpura dermatosis, eczema and other diseases. 1. Purpura: It is a subcutaneous hemorrhage caused by abnormalities in the structure and function of the blood vessel wall, abnormalities in the number or function of platelets, and so on, resulting in the leakage of red blood cells from the blood vessels to the skin, connective tissues, or mucous membranes, and it looks like a red blood spot on the skin. 2. Pigmented purpura dermatosis: the etiology is unknown and is associated with capillary wall lesions. Gravity and elevated venous pressure are important local triggers. This can lead to subcutaneous hemorrhage caused by leakage of red blood cells from the blood vessels into the skin, connective tissues or mucous membranes, resulting in what appears to be dark red blood spots on the skin, giving the appearance of paprika-like blotches. 3. Eczema: subcutaneous bleeding due to eczema may be caused by peripheral platelet destruction, resulting in thrombocytopenic purpura, which looks like red blood spots on the skin. Red blood spots on the skin may also be seen in allergies, coagulation disorders and other diseases, if the symptoms of red blood spots on the skin, persistent and unrelieved, you need to seek medical treatment.