An Overview of Platelet Disorders

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Platelets are one of three types of red blood cells in your body, all of which are produced by stem cells in your bone marrow. Platelets are responsible for forming blood clots to stop bleeding and help repair damaged blood vessels. They also help fight infection by activating immune cells.

Platelet disorders happen when there are too many or too few platelets in circulation or the platelets in circulation aren't functioning properly. There are numerous types of platelet disorders, which may either be acquired or inherited.

This article details the symptoms and causes of the most common platelet disorders. It also includes information about how platelet disorders are diagnosed and what treatments to expect if you have been diagnosed with one.

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Common Types of Platelet Disorders

The average healthy person has between 150,000 and 450,000 platelets per microliter of blood. Unlike red blood cells or hemoglobin, normal platelet numbers are not affected by age or gender.

Thrombocytopenia is the medical term for having a platelet count of fewer than 150,000 platelets. Thrombocytosis refers to having a platelet count above 450,000 platelets.

Platelet function disorders vary greatly in severity and characteristics. With some types of disorders, the number of platelets in circulation falls within the normal range, but for some reason, they aren't performing as they should.

Platelet disorders, in general, are rare, but the most common ones include:

  • Essential thrombocythemia: A rare chronic blood disorder in which the bone marrow produces too many platelets, increasing the risk of dangerous blood clots.
  • Immune thrombocytopenia: A disorder in which the immune system mistakenly attacks and destroys its own platelets, resulting in severe thrombocytopenia with and without bleeding.
  • MYH9-related disorders: A group of inherited platelet function disorders associated with hearing loss and kidney dysfunction.
  • Neonatal alloimmune thrombocytopenia: A disorder that occurs during pregnancy or shortly after birth when the mother's antibodies destroy the infant's platelets, causing excessive bleeding in the infant.
  • Reactive thrombocytosis: An elevated platelet count that develops due to a recent infection, iron-deficiency anemia, or a surgical procedure such as a splenectomy (spleen removal).
  • Congenital amegakaryocytic thrombocytopenia (CAMT): A rare disorder in which the bone marrow cannot produce platelets normally. It is congenital, meaning that it is present at birth.
  • Drug-induced platelet dysfunction: A disorder in which your body has an abnormal reaction to a medication, such as non-steroidal anti-inflammatory drugs like aspirin, and Plavix (clopidogrel)—a medication used to prevent blood clots after a heart attack or stroke.

Platelet Disorder Symptoms

Symptoms of platelet disorders can be very mild—so much so that many people don't realize they have a platelet disorder until they have surgery or dental work, give birth, or are badly injured.

Sometimes, a person may notice that something seems off with how they bruise or bleed. They may develop large bruises very easily or become alarmed to discover a large bruise and not know what caused it.

Other common symptoms that people with platelet disorders present to their doctors include the following:

Symptoms related to thrombocytosis can be much less obvious. Whereas thrombocytopenia causes excessive bleeding, thrombocytosis causes excessive clotting.

Therefore, symptoms related to thrombocytosis can mimic serious medical conditions caused by blood clots, like pulmonary embolism. Symptoms may include:

When to See a Doctor

Internal bleeding and bleeding into the brain are fatal. Call 911 immediately if you notice chest pain, blood in your urine or stool, or you notice neurological symptoms such as a sudden headache, vision changes, or slurred speech.


Platelet disorders may either be acquired, or a person may not be diagnosed until adulthood when symptoms present. Or, although rarer, platelet disorders can be inherited, with symptoms presenting in the first few months to years of life.

Researchers believe that people who develop platelet disorders likely have another preexisting or genetic deficiency that makes them more sensitive to various drugs, diseases, or herbs that affect platelet count or function.

The platelet disorder then develops when the hypersensitive person reacts to the disease or substance upon exposure to it. This reaction may change how the platelets function or how many platelets are made in their bone marrow.

Platelet disorders are most commonly drug-induced. Drugs, diseases, herbs, and supplements that are known to affect platelet function include:

  • Non-steroidal anti-inflammatory medications (NSAIDs): Aspirin, along with other pain-relieving NSAIDs like ibuprofen (Advil) and naproxen (Aleve), may prevent platelets from clumping together to form clots.
  • Antiplatelet drugs: Clopidogrel (Plavix), prasugrel (Effient), and other antiplatelet drugs used to prevent heart attack and stroke may also prevent clotting and lead to excessive bleeding.
  • Antibiotics: Drugs used to treat bacterial infections, particularly penicillins, can affect platelet function and cause excessive bleeding.
  • Selective serotonin reuptake inhibitors (SSRIs): Antidepressant medications like fluoxetine (Prozac) and citalopram (Celexa) may prevent clotting and cause excessive bleeding, especially when taken alongside blood thinning drugs.
  • Foods, herbs, alcohol: Ginkgo biloba, garlic, ginger, feverfew, turmeric, and several other herbs are known to affect platelet activity and prevent blood clots. Heavy alcohol drinking may also induce thrombocytopenia.
  • Kidney and liver disease: Thrombocytopenia is commonly seen in people with kidney or liver disease; people with either disease have a greater risk of excessive bleeding.
  • Lupus: People with this autoimmune disease develop certain antibodies that attack platelets, leading to thrombocytopenia.

Genetic abnormalities that affect platelet formation or function can also be passed down from one generation to the next. Thus, people with inherited platelet disorders usually have bleeding disorders in their family history.


Platelet disorders may affect how many platelets you have or how your platelets function. They may be acquired upon having an immune reaction to a substance or disease, or they may be inherited in your genes. Unexplained bruises and excessive bleeding are some of the first symptoms people notice.


The most common screening test for platelet disorders is a complete blood count (CBC). This simple blood test includes information about the blood cells, including the platelet count.

Your physician may request that your platelets be reviewed under the microscope—a process known as a blood smear. This will allow your physician to determine whether your platelets are the normal size or not.

Several inherited platelet function disorders result in larger platelets, which can be seen on the blood smear. Others may be missing critical components of the platelets called granules.

Because people with platelet function disorders often have a normal platelet count, doctors diagnose these disorders with coagulation studies, which evaluate how long it takes for blood to clot.

Platelet function disorders may be diagnosed with the following tests:

  • Bleeding time: A test used to assess platelet function, in which a doctor makes a small incision and then times how long it takes for bleeding to stop.
  • Platelet function assay: A lab test that measures how well platelets travel to the site of an injury and clump together to stop the bleeding.
  • Platelet aggregation testing: A lab test that assesses how well platelets clump together to form clots.
  • Platelet electron microscopy: A test used to diagnose hereditary platelet disorders, in which the platelets are assessed for structural abnormalities.

​If there are concerns that your bone marrow is not functioning correctly, a bone marrow biopsy may be required as part of the workup.


Treatment for platelet disorders is also varied and is determined by your specific diagnosis. Some platelet disorders may not require specific treatment, while others may only require treatment during acute events like bleeding.

  • Platelet transfusions may be used if you have serious bleeding. Platelet transfusions can be used for platelet function disorders (regardless of platelet count) and most platelet disorders with thrombocytopenia.
  • Steroids like prednisone may be used in immune-related platelet disorders, such as immune thrombocytopenia.
  • Intravenous immunoglobulin is commonly used in immune-related platelet disorders, such as immune thrombocytopenia and neonatal alloimmune thrombocytopenia.
  • Aspirin inhibits platelet function and can be used to prevent blood clots from forming in essential thrombocythemia.
  • Anti-fibrinolytic medications promote clotting on moist surfaces like the mouth, nose, or uterus. They can help control nosebleeds, gum bleeding, and menorrhagia or prevent bleeding after surgical procedures.

It is important to discuss with your physician what the best treatment is for you and your diagnosis. Tell your healthcare provider if you have any bleeding disorders in your family that you are aware of, and keep them informed about your treatment progress or any side effects that concern you.


Because platelet disorders affect how well your blood clots, people with platelet disorders have a higher risk of bleeding complications.

People with thrombocytopenia have a low number of platelets. As a result, it takes longer for their blood to clot, which puts them at-risk of serious bleeding.

This becomes especially concerning when the person falls, gets into an accident, or injures themselves; unless they get help right away, they may be more likely to bleed to death, or they may develop a life-threatening internal bleed and not realize it quickly enough.

On the other hand, people with thrombocytosis have a much higher platelet count, and as a result, they are more likely to develop a dangerous blood clot that leads to heart attack or stroke.

Most people with platelet disorders can live long, healthy lives by staying on top of their treatments and taking everyday precautions to prevent bleeding.

And, whether you have a platelet disorder or not, you can reduce your risk of dangerous blood clots by eating healthy and exercising regularly. Just be sure to talk to your doctor before starting a new diet or exercise routine to make sure it is safe for you.


While some platelet disorders are diagnosed during routine checkups, many people don't realize they have a platelet disorder until they are injured or develop large bruises for seemingly no reason.

Doctors can diagnose platelet disorders by examining how many platelets you have, what your platelets look like, and how well they clump together. The right treatment for your condition can reduce the risk of severe bleeding, dangerous blood clots, and long-term health problems.

A Word From Verywell

If you are living with a platelet disorder, ask your physician if you would benefit from getting care at a hemophilia treatment center (HTC). HTCs provide people with bleeding and platelet disorders access to preventive care, support services, and personalized care teams that can help you manage your disorder and prevent chronic health problems. Furthermore, people who use HTCs are 40% less likely to be hospitalized for bleeding-related issues.

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Amber Yates, MD
Amber Yates, MD, is a board-certified pediatric hematologist and a practicing physician at Baylor College of Medicine.