Immune Thrombocytopenic Purpura (ITP) Symptoms and Causes

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The body has enough work to do defending itself from the outside world, repairing injuries, and fighting off infections. So it seems unfair that there are also enemies within that body that are ready to attack. Such is the case with immune thrombocytopenic purpura (idiopathic thrombocytopenic purpura or ITP), where the body attacks and destroys platelets in the blood stream, leading to an increased risk of bleeding.

Red and white blood cells are the star players in blood.

  • Red blood cells are the carriers of hemoglobin so that the body can receive oxygen from the lungs and deliver it to the organs of the body in order for them to function.

  • White blood cells are the armies of the body, fighting off infection.

  • Platelets get no press and little respect (unless they are involved with a heart attack!). Their purpose is to begin the clotting process in the body. When a blood vessel is damaged, platelets are the first to arrive at the scene to plug the hole. Other blood proteins start to congregate to form fibrin that strengthens the platelet plug and ultimately form a clot. Without enough platelets, the bleeding repair process fails and blood can leak out where it doesn't belong.

Picture of a how blood clot is formed
Picture of how red blood cells and platelets form a blood clot

In ITP, the body's immune system doesn't recognize the surface of the platelet cell as part of the body. It coats the surface of the platelet cell with antibodies and the now damaged platelet is removed from the blood stream by the spleen, the organ whose job it is to clean and filter the blood of abnormal or damaged cells and other particles. If the platelet count drops too low, spontaneous bleeding can occur. The name, ITP, perfectly describes the situation. The immune system removes platelets and thrombocytopenia (thrombocyte=platelet + penia=low count, low platelet count) occurs, causing purpura, a characteristic type of bruising or bleeding of the skin.