What causes skin bruising?

When our body is bumped, if it is serious, bleeding will occur under the skin, and the skin will appear purple-blue from the outside. In fact, there is no need to worry too much about this situation. You just need to rest for a few days and you will slowly recover. After all, it is a serious injury rather than a disease. However, there are also some friends whose skin still has such condition even though they are not injured. So, what causes skin congestion?

Qualitative platelet defects are a group of bleeding diseases caused by defects in platelet adhesion, aggregation, release, procoagulant function and arachidonic acid metabolism. It is divided into two categories: congenital and acquired, and most of the children have congenital hereditary diseases. The common feature is that the platelet count is high but there is no obvious decrease, while the platelet function test is abnormal: such as prolonged bleeding time, decreased prothrombin consumption, poor thromboplastin generation, and a positive arm test. However, the coagulation time, prothrombin time, thrombin time and partial thromboplastin time were all normal.

In this disorder, the number of platelets is normal, but they cannot form blood clots normally and bleeding is prolonged. Abnormal platelet function may be due to endogenous platelet defects or due to exogenous factors that change normal platelet function. Platelet defects may be inherited or acquired. Tests of the coagulation phase of hemostasis (eg, PTT and PT) are normal in most, but not all, cases.

Platelets have functions such as adhesion, aggregation, and release. When vascular endothelial cells are damaged, platelets react quickly, first adhering to the damaged area, then aggregating to form clots and releasing a variety of procoagulants or vasoactive substances, causing thrombus formation, thereby achieving the purpose of hemostasis. In addition, platelets also have the function of promoting fibrinolysis.

Platelet dysfunction refers to a bleeding disease caused by defects in platelet adhesion, aggregation, release, and coagulation, that is, it refers to abnormal platelet quality. The clinical features are mucosal bleeding, normal or slightly decreased platelet count, prolonged bleeding time, poor clot retraction, and platelet deformities.

There are two common diseases. One is congenital platelet defect, which is seen in giant platelet syndrome, thrombasthenia, congenital connective tissue disease, etc. The second is acquired platelet deficiency, which is seen in uremia, myelodysplastic syndrome, drug-induced platelet dysfunction, dysproteinemia, liver disease, disseminated intravascular coagulation, etc.