When you have the rare but treatable disorder known as aplastic anemia, your marrow -- the spongy substance inside your bones -- stops making new blood cells. Sometimes it stops making just one type, but more often you become low on all three: red and white cells, and platelets.
It can develop slowly or come on suddenly. If your blood count gets low enough, it can be life-threatening.
A healthy person usually has a platelet count of 150,000 to 400,000. You have thrombocytopenia if your number falls under 150,000.
If you're wondering what the long name means, here's how it breaks down: "thrombocytes" are your platelets and "penia" means you don't have enough of something. Put those terms together, and you get "thrombocytopenia."
Thrombocytopenia happens when your body makes too few platelets, or the platelets you have are trapped in the spleen, or they are destroyed.
It can run in families. But you can also get it from many medical conditions and some drugs.
If your spleen is enlarged, that can trap platelets, and they won't move through your body.
Sometimes your immune system, which is supposed to fight off disease, attacks healthy cells. When it attacks your platelets, that's called idiopathic thrombocytopenic purpura (ITP).
In other cases, your body just uses too many platelets, leaving you without enough of them. That can happen if you have an autoimmune disease, like rheumatoid arthritis or lupus. The same is true if you have thrombotic thrombocytopenic purpura (TTP), which uses a lot of platelets to make small blood clots throughout your body.
Your blood platelets can also be destroyed because of:
Medication side effects, including drugs for heart problems, seizures, and infections
Usually, thrombocytopenia has no symptoms. But when you do have them, they can include:
Bleeding, most often from the gums or nose. Women with thrombocytopenia may have heavier or longer periods or breakthrough bleeding. You may also see blood in your pee or poop.
Red, flat spots on your skin, about the size of a pinhead. You see these mostly on your legs and feet, and they may appear in clumps. Your doctor may call them petechiae.
Blotches and bruises. You might have large areas of bleeding under the skin that don't turn white when you press on them. You also might see what look like the bruises you get from a bump or being hit. They could be blue or purple and change to yellow or green over time. The difference is, these are caused from the inside, by the sudden leaking from tiny blood vessels. The medical name for these is purpura.
Severe thrombocytopenia can cause a lot of bleeding after an injury, such as a fall.