What happens when red blood spots appear on the skin?

Skin problems are very prevalent in modern life. Most people have suffered from skin diseases at some time or another. There are many types of skin diseases, with varying degrees of impact. For example, lupus erythematosus is a disease with a very high impact, while a common rash will not cause much impact on health. Some skin diseases appear particularly strange and are almost extremely rare. For example, some people have red blood spots on their skin without any stimulation. These blood spots are densely distributed, but the patient does not feel anything. So, what is the cause of the red blood spots on the skin? How did it happen? Let’s take a look at the explanation below.

Skin hemorrhages refer to extensive or localized bleeding under the skin and mucous membranes, forming red or dark red spots on the skin and mucous membranes, with a diameter of about 3 to 5 mm or larger. Those that fade when pressed are called purpura. Usually, those with a diameter of less than 2 mm are called hemorrhages.

(1) Extravascular factors: If the tissues surrounding blood vessels become weak due to degeneration, atrophy and relaxation, bleeding is likely to occur and purpura may form. Extravascular factors are more common in senile or cachectic purpura. Capillaries and small blood vessels can be ruptured and bleed by slight external force, leading to purpura.

(2) Vascular factors: refers to purpura caused by damage to the capillary walls, which causes blood to leak out of the blood vessels. Purpura caused by vascular factors accounts for the first place among all purpura. When small blood vessels in a normal person are injured, the blood vessels immediately undergo reflex contraction and local blood flow slows down to promote hemostasis. If the peripheral blood vessels are fragile, permeable and vasomotor function is abnormal, hemorrhagic purpura may easily occur due to blood infiltration into and out of the blood vessels. In addition, there is a type of increased fragility of the blood vessel walls for unknown reasons, which is common in women. Purpura may disappear on its own without any adverse consequences. This is called simple purpura.

(3) Platelet factors: Platelets play an important role in the hemostasis process. Thrombocytopenia or platelet function deficiency will weaken or lose the hemostatic function, which can easily lead to purpura. In addition, hypersplenism, lupus erythematosus, uremia, etc. can also cause thrombocytopenia. Platelet function deficiency diseases include hemorrhagic thrombocythemia, thrombasthenia, etc. Laboratory tests are of great significance for the diagnosis of purpura caused by platelet factors, which generally manifests as prolonged bleeding time, poor clot retraction and thrombocytopenia.