Platelets are the blood cells responsible for the formation of blood clots. They are produced in the bone marrow.
A decrease in the number of platelets (thrombocytopenia) increases the risk of significant blood loss in the event of trauma (cut, ecchymosis) or other bleeding (mouth, nose, digestive tract). It often manifests by the ease of ecchymosis (bruising) or the appearance of red spots on the skin (petechiae or purpura depending on the size). Thrombocytopenia can be caused by, among other things, autoimmune disease, medications or toxins, viral infection, acute alcoholism, bone marrow disease (myelodepression), etc.
Too many platelets (thrombocytosis) increases the risk of clot formation in the blood vessels (phlebitis, etc.). These clots can also manifest as migraines, changes in the field of vision, etc. Thrombocytosis increases the risk of pulmonary embolism, heart attack and stroke. Thrombocytosis can be reactive (inflammatory disease, iron deficiency, spleen disorder, cancer, stress, etc.). It can also be “essential,” following bone marrow disease (myelodysplastic and myeloproliferative syndromes).