Low platelet count (thrombocytopenia): Causes, treatment, and more Health ConditionsHealth ConditionsAlzheimer's & DementiaAnxietyArthritisAsthma & AllergiesBreast CancerCancerCardiovascular HealthCOVID-19Dermatology & SkincareDiabetesEnvironment & SustainabilityExercise & FitnessEye HealthHeadache & MigraineHealth EquityHIV & AIDSHuman BiologyInflammatory Bowel DiseaseLeukemiaLGBTQIA+Men's HealthMental HealthMultiple Sclerosis (MS)NutritionParkinson's DiseasePsoriasisSexual HealthWomen's HealthDiscoverNewsLatest NewsOriginal SeriesMedical MythsHonest NutritionThrough My EyesNew Normal HealthPodcastsHow to understand chronic painWhat is behind vaccine hesitancy?The amazing story of hepatitis C, from discovery to cureNew directions in dementia researchCan psychedelics rewire a depressed, anxious brain?Why climate change matters for human healthToolsGeneral HealthDrugs A-ZHealth HubsHealth ToolsBMI Calculators and ChartsBlood Pressure Chart: Ranges and GuideBreast Cancer: Self-Examination GuideSleep CalculatorHealth ProductsAffordable Therapy OptionsBlood Pressure MonitorsDiabetic SuppliesFitness TrackersHome GymsGreen Cleaning ProductsHow to Shop for CBDQuizzesRA Myths vs FactsType 2 Diabetes: Managing Blood SugarAnkylosing Spondylitis Pain: Fact or FictionConnectAbout Medical News TodayWho We AreOur Editorial ProcessContent IntegrityConscious LanguageNewslettersSign UpFollow UsMedical News TodayHealth ConditionsDiscoverToolsConnectSubscribe What are the causes of a low platelet count Medically reviewed by Meredith Goodwin, MD, FAAFP — By Markus MacGill and Adam Rowden — Updated on June 29, 2022Platelets are blood cells that help the blood clot. Clotting allows the blood to form plugs in blood vessel injuries to stop blood loss. Thrombocytopenia is the name for a low platelet count. A reduced platelet count in the blood is not always a serious problem. However, the condition affects the ability of the blood to clot. If a person’s blood does not clot, a wound may bleed severely. This can have serious complications in some cases. This article examines the conditions, medications, and substances that can cause a low platelet count. It also outlines how to recognize the symptoms and what to expect from treatment. What is thrombocytopenia Share on PinterestEd Reschke/Yoshiyoshi Hirokawa/Getty ImagesThrombocytopenia is a condition that occurs when the platelet count in a person’s blood is too low. The normal platelet count in adults is 150,000–450,000 platelets per microliter (µl) of blood. A person with thrombocytopenia will have a platelet count below 150,000/µl. Thrombocytopenia may make it difficult for the body to stop bleeding following an injury. Bleeding can occur inside the body, beneath the skin, or at the surface of the skin. People with thrombocytopenia usually do not experience serious bleeding until their platelet count is very low. What is ITP ITP refers to idiopathic thrombocytopenic purpura, a rare condition that is also known as immune thrombocytopenia. The condition involves bleeding-induced rashes that occur as a result of a low platelet count. Idiopathic means that the cause is not known. In people with ITP, the immune system attacks platelets, which prevents the blood from clotting properly. This can sometimes occur following an infection. What are the causes of a low platelet count There are two main factors that cause a person to have a low platelet count: an underlying health condition or a medication. These factors can lower the platelet count by affecting the production, storage, use, or destruction of platelets. Medical conditions that can cause a low platelet count A low platelet count may occur due to:the bone marrow not producing enough plateletsthe body destroying or using up the platelets that the bone marrow does producethe spleen holding onto too many platelets, meaning that the amount in the blood is too low Certain medical conditions can also cause a person to have a low platelet count. These include:Aplastic anemia: This rare blood condition occurs when the bone marrow stops making an adequate number of new blood cells.Autoimmune diseases: Certain autoimmune diseases can cause a person’s immune system to mistakenly attack and destroy their platelets. Diseases that can do this include ITP, lupus, and rheumatoid arthritis.Cancer: Some cancers, such as leukemia or lymphoma, can damage a person’s bone marrow and destroy blood stem cells. This can cause the person’s stem cells to stop growing healthy blood cells. Some cancer treatments, including radiation therapy and chemotherapy, may also destroy stem cells.Conditions that cause blood clots: Some conditions cause blood clots to develop. These conditions include thrombotic thrombocytopenic purpura (TTP) and disseminated intravascular coagulation (DIC). These conditions can cause the body to use up all of the available platelets, leading to a low platelet count.Infections: Bacterial or viral infections may lower a person’s platelet count temporarily.Large spleen: If a person’s spleen is large, it may store too many platelets. This can cause a low platelet count in the person’s blood.Surgery: In some cases, artificial heart valves, blood vessel grafts, or machines and tubing for blood transfusions or bypass surgery may destroy a person’s platelets. Pregnancy may sometimes cause a person to develop mild thrombocytopenia. The exact reason for this is unknown, but it seems to be more common close to delivery. Medications and substances that can cause a low platelet count Various substances can cause a person to have a low platelet count, including:medicationspoisonous substances, such as pesticides, arsenic, and benzeneheavy alcohol consumptionquinine, which is in tonic water and some tablets for leg cramps If a substance is causing a person’s low platelet count, a doctor may suggest that they stop taking it. Doing so should return the platelet count to normal. If the cause is a drug that a person is taking for a different condition, the prescribing doctor might change the medication. Over-the-counter (OTC) medications that can cause a low platelet count include:acetaminophenibuprofennaproxenaspirin Prescription medications that can cause thrombocytopenia include:amiodaroneampicillin and other antibioticscimetidineglycoprotein IIb/IIIa inhibitors, including abciximab, eptifibatide, and tirofibanheparin piperacillinseizure medications, such as carbamazepinesulfonamides, such as trimethoprim-sulfamethoxazolevancomycin Symptoms The symptoms of a low platelet count only occur at severely low levels. A count that is only slightly lower than normal may not produce symptoms. If the count is low enough to cause spontaneous bleeding, an individual may notice minor bleeds that create small, round, dark red spots on the skin called petechiae. Several petechiae can merge to form bruise-like rashes called purpura. ITP can also cause the gums or nose to bleed without reason and lead to the presence of blood in the urine or stools. In these cases of ITP, platelet counts are typically below 20,000/µl. What are platelets Platelets are a crucial component of the blood. They are responsible for repairing tissue damage and play a vital role in the blood-clotting system, helping stop bleeding and heal wounds. Blood clotting is also known as hemostasis. The bone marrow produces platelets, and they are present in a person’s blood and spleen. How do platelets stop bleeding If damage occurs to the wall of a blood vessel, the vessel exposes a substance that activates platelets. Activated platelets trigger further events that bring in more platelets, and a blood clot starts to form. This serves to plug any leak. Activated platelets also release sticky proteins to help form the clot. A protein known as fibrin forms a mesh of threads that holds the plug together. Normal ranges A platelet count measures the concentration of platelets in the blood. A technician will carry this test out in a laboratory. A normal platelet count is 150,000–450,000 platelets/µl. When the number of platelets is low, this concentration reduces. Females usually experience a platelet count that varies slightly during the menstrual cycle and can fall near the end of pregnancy. The following platelet counts carry the risk of serious bleeding:Between 20,000 and 50,000/µl: There is more risk of bleeding in relation to an injury.Less than 20,000/µl: Bleeding happens even without an injury.Below 5,000/µl: Spontaneous bleeding can be severe and a risk to life. Diagnosis To diagnose a low platelet count, a doctor may begin by asking some questions and performing a physical examination. The questions might cover symptoms, family history, and medications. The examination will assess for skin rashes and bruising. A laboratory platelet count will confirm the diagnosis, showing the exact concentration of platelets in the blood. The doctor is likely to perform other blood tests at the same time. These may include:a complete blood count (CBC)a blood smear test, which involves looking at platelets under a microscopeother blood tests to assess blood clottingbone marrow tests There are two types of bone marrow tests: a bone marrow aspiration and a bone marrow biopsy. Both tests require a doctor to use a needle to take a sample of the bone marrow for examination. Aspiration involves the collection of a small amount of fluid, whereas a biopsy involves the collection of some soft tissue. A doctor may diagnose thrombocytopenia after ruling out other causes of a low platelet count. Treatment Slightly low platelet counts that do not produce symptoms may not require treatment. For platelet counts low enough to cause physical effects, a doctor will address the cause directly. There is a wide range of possible causes. Treatment could involve switching medication or attempting to resolve an underlying medical condition. For cases of ITP, the treatment may involve drugs that suppress the immune system, such as a corticosteroid drug called prednisone. In severe cases, a blood transfusion may be necessary. If there are no increases in platelet count after a year, a surgeon may remove the spleen in a procedure called a splenectomy. People with extremely severe or emergency presentations of low platelet count can receive a transfusion of platelets. Living with thrombocytopenia People who have a diagnosis of this condition can reduce the risk of complications by:taking care to avoid bumps and injuries that might lead to bruises and cutsensuring that all of the healthcare professionals who treat them know about this condition, as it can influence treatment decisionstaking care with OTC drugs, such as aspirin, acetaminophen, ibuprofen, and naproxenavoiding infections where possible, if a person has undergone a splenectomy Anyone who experiences any unusual symptoms or has other concerns should discuss these with a doctor. Summary Platelets are cells in a person’s blood that play an important role in blood clotting. They help form blood clots to stop bleeding and heal wounds. If a person has a low platelet count, called thrombocytopenia, their blood might not clot properly. This can lead to symptoms such as blood loss and bruising. There are many possible causes of a low platelet count, including medical conditions and exposure to certain substances. Substances that can lower a person’s platelet count include some medications, poisonous substances, alcohol, and quinine. Slightly low platelet counts that do not produce symptoms may not require treatment. However, if symptoms are present, treatment may be necessary. The treatment can involve switching medications, reducing exposure to certain substances, or treating the underlying medical condition that is causing the low platelet count. Last medically reviewed on June 29, 2022DermatologyBlood / HematologyInfectious Diseases / Bacteria / Viruses 8 sourcescollapsedMedical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.Blood tests. (2022).https://www.nhlbi.nih.gov/health/blood-testsJinna, S., et al. (2022). Thrombocytopenia [Abstract].https://pubmed.ncbi.nlm.nih.gov/31194365/Kuter, D. J. (2022). Immune thrombocytopenia (ITP).http://www.merckmanuals.com/professional/hematology-and-oncology/thrombocytopenia-and-platelet-dysfunction/immune-thrombocytopenia-itpKuter, D. J. (2022). Overview of platelet disorders.http://www.merckmanuals.com/professional/hematology-and-oncology/thrombocytopenia-and-platelet-dysfunction/overview-of-platelet-disordersPeriayah, M. H., et al. (2017). Mechanism action of platelets and crucial blood coagulation pathways in hemostasis.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5767294/Platelet disorders. (2022).https://www.nhlbi.nih.gov/health/platelet-disordersPlatelet. (n.d.).https://www.cancer.gov/publications/dictionaries/cancer-terms/def/plateletThrombocytopenia. (2022).https://www.nhlbi.nih.gov/health-topics/thrombocytopeniaFEEDBACK:Medically reviewed by Meredith Goodwin, MD, FAAFP — By Markus MacGill and Adam Rowden — Updated on June 29, 2022 Latest newsWhat sets 'SuperAgers' apart? Their unusually large neuronsOmega-3 may provide a brain boost for people in midlifeSeasonal affective disorder (SAD): How to beat it this fall and winterCDC: Monkeypox in the US 'unlikely to be eliminated in the near future'Why are more women prone to Alzheimer's? 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