Thrombocytopenia (low platelet count)

Thrombocytopenia is low blood platelet count. Platelets, also called thrombocytes, are colorless blood cells that help blood clot. Platelets stop bleeding by clumping together and forming plugs in blood vessel injuries.

Thrombocytopenia (throm-boe-sie-toe-PEE-nee-uh) can happen because of conditions or medicines that affect the circulation, production or destruction of blood platelets. Thrombocytopenia can affect both children and adults.

Thrombocytopenia can be mild and cause no symptoms. If platelets become too low, there is a risk of serious bleeding after an injury or during surgery. Rarely, dangerous internal bleeding can occur.

Treatments address the underlying condition causing the low platelet count. In some cases, treatment includes a transfusion of donor platelets.

Symptoms of thrombocytopenia may include:

• Easy or excessive bruising, called purpura, on the skin or inside the mouth.
• Pinpoint-sized dots on the skin, called petechiae, that may be red, purplish or brownish.
• Bleeding from minor cuts that lasts longer than usual.
• Bleeding from the gums or nose.
• Blood in urine or stools.
• Unusually heavy menstrual flows.

When to see a doctor

Make an appointment with your healthcare professional if you have symptoms of thrombocytopenia.

Bleeding that won't stop is a medical emergency. Seek immediate help for bleeding that can't be controlled by the usual first-aid techniques, such as applying pressure to the area.

Platelets are produced in bone marrow. Each platelet lives about 7 to 10 days, so bone marrow is always renewing the supply and releasing it into the blood.

Thrombocytopenia is a platelet count lower than 135,000 platelets per microliter of blood in men and lower than 157,000 platelets per microliter of blood in women. Some clinics or labs may use slightly different numbers.

A large, rapid drop in platelets may result in a count higher than these targets, but this drop may still indicate a condition affecting platelet levels.

The causes of a decline in a platelet count fall into three categories:

• Platelets are trapped and not circulating.
• Not enough platelets are made.
• Platelets are being destroyed or used up.

Trapped platelets

The spleen is a small organ about the size of your fist situated just below your rib cage on the left side of your abdomen. The spleen works to fight infection and filter unwanted material from your blood.

An enlarged spleen — which can be caused by a number of disorders — can hold too many platelets. This decreases the number of platelets circulating in the bloodstream.

Decreased production of platelets

Platelets are produced in your bone marrow. Factors that can decrease platelet production include:

• Cancers and other diseases of the bone marrow.
• Chemotherapy medicines and radiation therapy.
• Heavy alcohol consumption.
• Poor nutrition, particularly low iron, folate and vitamin B12.
• Inherited disorders.
• Certain viral infections.

Platelets destroyed or used up

Some conditions cause your body to use up or destroy platelets faster than they're produced. This leads to a shortage of platelets in your bloodstream. Examples of such conditions include:

• Medicines. The destruction of platelets may be a side effect of some medicines. Usually, this means the medicine causes the immune system to see platelets as things that needs to be destroyed. Examples include quinine, sulfa-containing antibiotics and anticonvulsants.
• Immune system disorders. In autoimmune disorders, the immune system attacks healthy tissue instead of germs. Autoimmune disorders that can destroy platelets include immune thrombocytopenia with purpura, lupus and others.
• Infections. Bacterial or fungal infections in the blood can directly destroy platelets. Severe bacterial or viral infections, including HIV and hepatitis C, can cause the immune system to attack platelets.
• Pregnancy. Thrombocytopenia can develop in pregnancy, most often late in the pregnancy. It usually doesn't cause symptoms and improves after delivery. Thrombocytopenia with preeclampsia increases the risk of complications. Preeclampsia results in high blood pressure and signs of kidney dysfunction.

Low platelets and blood clot risk

Sometimes a platelet count is low because platelets are activated as if they were responding to an injury. The activated platelets clump together to form clots when there is no injury. The count is low because the platelets are used up faster than they are being replaced.

These blood clots create a serious risk of blocked blood circulation that can cause life-threatening tissue or organ damage.

Conditions or factors that can cause a low platelet count with blood clotting include:

• Heparin use. Heparin is a blood-thinning medicine. Sometimes it binds to platelets and activates them.
• Thrombotic microangiopathies. This is a group of disorders that result in multiple clots in tiny blood vessels that can occur in any tissues of the body. These may be related to an autoimmune disorder, infection, medicines or other medical conditions.
• COVID-19. Rarely, a COVID-19 infection or a COVID-19 vaccine can trigger the immune system to activate platelets.

Generally, the lower the platelet count, the greater the risk for complications of excessive bleeding or clotting.

A platelet count is checked before having procedures that involve bleeding, such as surgery. Rarely, internal bleeding can happen without injury when a platelet count is very low.

Your healthcare professional will ask you a number of questions about symptoms, health history, medicines and symptoms. The following will likely be used to determine whether you have thrombocytopenia:

• Blood test. A complete blood count determines the number of blood cells, including platelets, in a sample of your blood. Your healthcare professional may compare the results of a recent test with past tests.
• Blood smear. This is a lab test to look at a sample of blood under a microscope to count platelets. A specialist looks for clumping or irregular platelets and looks at other blood cells.
• Physical exam. Your healthcare professional will look for signs of bleeding under your skin, gums or lining of your mouth. Your care professional will examine the size or tenderness of the spleen, liver and lymph nodes.

Your care professional might suggest other tests and procedures to determine the cause of your condition depending on your signs and symptoms.

People with mild thrombocytopenia might not need treatment. Treatments for more-serious cases depend on the cause and the risk of complications.

Treating the cause may include:

• Stopping a medicine that likely caused thrombocytopenia.
• Treating an underlying disease, such as an infection or cancer.

Other treatments might involve:

• Medicines. If thrombocytopenia is related to an immune system disorder, medicines may be used to control immune system activity. The most common medicine is a corticosteroid.
• Platelet transfusions. Platelet transfusions use donor platelets to boost the number of platelets in the bloodstream. They are delivered through a needle into a vein. Platelet transfusions may be used when a platelet count is too low.
• Plasma exchange. In some cases, a severe risk of blood clotting may require a plasma exchange. With this procedure, blood circulates from the person to a machine that removes plasma and replaces it with donor plasma or a plasma substitute. The blood then circulates back to the person.
• Surgery. Surgery to remove the spleen is called a splenectomy. This may be done to remove an enlarged or diseased spleen. Removing the spleen also may be needed when other treatments do not improve a low platelet count.

If you have thrombocytopenia, try to:

• Avoid activities that could cause injury. If a job carries a risk of injury, use protective gear and follow safety guidelines. Ask your healthcare professional if you should avoid contact sports that increase the risk of injury. Wear a helmet when bicycling, skateboarding or participating in similar activities.
• Avoid alcohol. Alcohol slows the production of platelets in your body. Ask your care professional whether it's OK for you to drink alcohol.
• Use caution with nonprescription medicines. Pain medicines, such as aspirin and ibuprofen (Advil, Motrin IB, others), can prevent platelets from working properly. Acetaminophen (Tylenol, others) is a better alternative.

If you have symptoms of thrombocytopenia, start by seeing your primary healthcare professional. Also, a low platelet count may be found in a complete blood count test during an annual checkup or with tests for another condition.

You may be referred to a specialist in blood diseases, called a hematologist, or another specialist depending on the possible cause of a low platelet count.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet.

Make a list of:

• Warning signs you've noticed, such as any unusual bruising or bleeding or any rashes. Note when they began. Write down any other symptoms even if they don't seem related to your main concern.
• Key personal information, including recent illnesses or medical procedures such as a blood transfusion, major stresses or recent life changes.
• All medicines, vitamins and other supplements you take, including doses and the reasons for taking them.
• Questions to ask your healthcare professional.

Take along a family member or friend, if possible, to help you remember the information you receive.

Questions to ask your healthcare professional might include:

• How many platelets do I have in my blood?
• Is my platelet count dangerously low?
• What is causing my thrombocytopenia?
• Do I need more tests?
• Is my condition likely temporary or chronic?
• What are my treatment options?
• What will happen if I do nothing?
• Are there any restrictions that I need to follow?
• Are there printed materials I can have? What websites do you recommend?

What to expect from your doctor

Questions your healthcare professional might ask include:

• Do you bruise easily?
• Have you experienced excessive bleeding with minor injuries?
• Have you have had bleeding from your gums?
• Is there a history of bleeding disorders or thrombocytopenia in your family?
• Have you recently started a new medicine?
• Are there medicines you take off and on?
• Where have you traveled recently?
• Have you recently had or been exposed to a bacterial or viral disease?
• How much alcohol do you drink?
• Do you have any restrictions in your diet?
• Have you had any unexpected weight loss or change in appetite?
• Have you had any bone pain?