Patient Basics: Thrombocytopenia (Low Platelet Count)

Thrombocytopenia means a low platelet count. Platelets are tiny cells in the blood that stick together to plug a cut and start a clot. A count that is only a little low often causes no problems and turns up by chance on a routine blood test. A very low count can lead to easy bruising and bleeding, so finding the cause is the main job.

Key points

• A normal platelet count is about 150,000 to 450,000 per microliter of blood. Below 150,000 counts as thrombocytopenia.
• Common causes include medicines, infections, liver disease, an immune reaction against platelets, and problems in the bone marrow.
• Signs include easy bruising, tiny red or purple dots on the skin, nosebleeds and bleeding gums.
• Many people with a mild drop need no treatment. Others need medicine, or a platelet transfusion if the count is very low.
• Bleeding that won’t stop, black stools or a sudden bad headache need emergency care.

What causes thrombocytopenia

Platelets are made in the bone marrow, the soft tissue inside bones. They live about 7 to 10 days in the blood. The count drops when the marrow makes too few, when the body destroys or uses them up too fast, or when they get trapped in the spleen.

The bone marrow makes too few

• Chemotherapy and radiation
• Leukemia, lymphoma and other cancers that spread into the marrow
• Aplastic anemia and myelodysplastic syndrome (conditions where the marrow fails)
• Heavy drinking over a long time
• Very low vitamin B12 or folate
• Viral infections such as HIV, hepatitis C and mono

Platelets are destroyed or used up

• Immune thrombocytopenia (ITP). The immune system makes antibodies that attack platelets. In children it often follows a virus and clears up on its own. In adults it more often lasts.
• Medicines. Heparin, a blood thinner given in the hospital, can trigger a reaction called HIT. Some antibiotics, seizure medicines and quinine can also lower the count.
• Autoimmune diseases such as lupus.
• Serious infection (sepsis) and rare clotting disorders such as TTP, where small clots form all over the body and use up platelets.
• Pregnancy. A mild drop late in pregnancy is common and usually harmless. A sharp drop with high blood pressure can be part of a serious problem called HELLP syndrome.

Platelets are trapped in the spleen

An enlarged spleen holds on to more platelets than usual. Liver scarring (cirrhosis) is the most common reason.

Sometimes the count only looks low. Platelets can clump together in the test tube, and the lab machine misses them. A repeat test in a different tube sorts this out.

Thrombocytopenia symptoms

Many people have no symptoms until the count is quite low. Signs to watch for:

• Bruises that appear easily or without a reason you remember
• Petechiae (pin-sized red or purple dots), often on the lower legs
• Larger purple patches under the skin (purpura)
• Nosebleeds or bleeding gums
• Small cuts that keep bleeding
• Periods that are much heavier than usual
• Blood in urine, or red or black stools

Serious bleeding without an injury is rare until the count falls below about 10,000 to 20,000.

How it’s diagnosed

A complete blood count (CBC) measures platelets. If the number is low, your doctor will usually:

• Repeat the test and look at your blood under a microscope (a blood smear)
• Go over every medicine and supplement you take, and how much alcohol you drink
• Check your liver, kidneys, vitamin levels, and tests for HIV and hepatitis C
• Feel for an enlarged spleen, and sometimes order an ultrasound

If the cause is still unclear, or other blood counts are also off, a blood specialist (hematologist) may take a small sample of bone marrow from the hip bone.

How thrombocytopenia is treated

Treatment depends on the cause and on how low the count is. A mild drop with no bleeding may only need repeat blood tests.

• Treat the cause. Stopping a medicine, treating an infection, cutting back on alcohol or replacing a vitamin often brings the count back up.
• For ITP, steroids such as prednisone or dexamethasone are often the first treatment. Immune globulin (IVIG) through a vein raises the count quickly. Medicines that push the marrow to make more platelets include eltrombopag, romiplostim and avatrombopag. Rituximab or surgery to remove the spleen are other choices for long-lasting cases.
• For HIT, all heparin is stopped and a different blood thinner is started, because HIT can cause dangerous clots.
• For TTP, treatment in the hospital with plasma exchange is urgent.
• Platelet transfusion is used for active bleeding, a very low count, or before surgery.

Living with a low platelet count

• Ask before taking aspirin, ibuprofen or naproxen. They make platelets work less well.
• Limit alcohol.
• Use a soft toothbrush and an electric razor.
• Skip contact sports and activities with a high chance of falls until your count is safe for them.
• Tell your dentist and any surgeon about your count before a procedure.

When to see a doctor

• You bruise easily or see tiny red dots on your skin
• Your gums or nose bleed often
• Your periods are much heavier than normal
• A blood test showed a low count and you haven’t had follow-up

Call 911 or go to an emergency department for bleeding that won’t stop with pressure, vomiting blood, black or bloody stools, or a sudden severe headache, confusion or weakness. These can be signs of serious internal bleeding.

Common questions about thrombocytopenia

What platelet count is dangerously low?

Below about 50,000, bleeding after an injury or surgery becomes more likely. Below about 10,000 to 20,000, bleeding can start without any injury, including inside the body. When deciding on treatment, your doctor weighs your symptoms and the cause as well as the number.

Can thrombocytopenia go away?

Yes, often. A low count from a virus, a medicine or alcohol usually recovers within days to weeks once the trigger is gone. Most children with ITP get better within months. In adults, ITP more often lasts, but treatment can keep the count high enough to prevent bleeding.

Is thrombocytopenia a sign of cancer?

Usually not. Medicines, infections, liver disease and ITP are much more common causes. Leukemia, lymphoma and cancer in the bone marrow can lower platelets, often along with other blood counts. Your doctor will look for these if other tests point that way.

Can food raise my platelet count?

No food has been shown to raise platelets in most people. If you lack vitamin B12 or folate, replacing them helps. Cutting back on alcohol helps too. Tonic water contains quinine, which can lower platelets in some people.

Questions to ask your doctor

• What is causing my low platelet count?
• What count is safe for my work, sports and daily life?
• Should I stop or avoid any of my medicines?
• How often do I need blood tests?
• Which bleeding signs mean I should go to the emergency department?

Learn more

• Thrombocytopenia (National Heart, Lung, and Blood Institute)
• Thrombocytopenia (MedlinePlus, U.S. National Library of Medicine)

This guide is general information and doesn’t replace advice from your own doctor. Last updated October 2026.