How do you diagnose ITP?
Take Home Message: ITP is a diagnosis of exclusion though often can be diagnosed pretty quickly with a good history and physical and a few labs, including LFTs, BMP, CBC with peripheral smear and PT/PTT. If any of these labs are abnormal or patient’s H&P lead you to suspect other causes of thrombocytopenia, then further work up is warranted.
Source: International consensus report on the investigation and management of primary immune thrombocytopenia. Blood. 2010 Jan 14;115(2):168-86.
ITP is a diagnosis of exclusion, therefore you must rule out other causes such as bone marrow problems or hemolysis. Therefore the following work-up is recommended:
- LFTs to rule out liver disease including alcoholic cirrhosis
- Peripheral smear to look for bone marrow disease, other lines affected:
- Tear drops, blasts, Auer rods: myelodysplastic syndrome
- Blasts: leukemias – acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL)
- Clinical clues of wt loss, fever: malignancies
- Tear drops, anemia, leokopenia: fibrosis – Myeloid Metaplasia with Myelofibrosis (MMM)
- B12, folate deficiency, viral syndrome: aplastic anemia
- hematologic conditions
- disseminated intravascular coagulation
- low platelet count
- elevated activated partial thromboplastin time (aPTT)
- elevated prothrombin time (PT)
- low levels of 1-2 clotting factors and inhibitors (for example, antithrombin, fibrinogen)
- elevated fibrin degradation products (FDPs) or D-dimer
- thrombotic thrombocytopenic purpura (TTP) (low plts with microangiopathic hemolytic anemia and neurological symptoms )
- hemolytic-uremic syndrome (assoc with Ecoli diarrhea)
- hemolytic anemia – hematocrit 9 /L
- serum creatinine level greater than upper limit for age
- absence of other reasons for coagulopathy, such as sepsis
- disseminated intravascular coagulation
- heparin-induced thrombocytopenia (HIT) – check HIT antibodies if suspect this in a patient who has received heparin products
- hypersplenism- myelo/lymphoproliferative diseases
- pregnancy-associated disorders
- gestational thrombocytopenia
- hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome
- folate deficiency
- massive obstetrical hemorrhage (postpartum hemorrhage)
- antiphospholipid antibody syndrome
- transfusion reactions, posttransfusion purpura
- pseudo-thrombocytopenia due to (EDTA)-dependent platelet agglutination (EDTA used in routine blood counts
The workup for immune thrombocytopenia (ITP) starts with a complete blood cell (CBC) count. The hallmark of ITP is isolated thrombocytopenia; anemia and/or neutropenia may indicate other diseases
On peripheral blood smear, the morphology of red blood cells (RBCs) and leukocytes is normal. The morphology of platelets is typically normal, with varying numbers of large platelets. Some persons with acute ITP may have megathrombocytes or stress platelets, reflecting the early release of megakaryocytic fragments into the circulation. If most of the platelets are large, approximating the diameter of RBCs, or if they lack granules or have an abnormal color, consider an inherited platelet disorder.
Clumps of platelets on a peripheral smear prepared from ethylenediaminetetraacetic acid (EDTA)–anticoagulated blood are evidence of pseudothrombocytopenia.  The diagnosis of this type of pseudothrombocytopenia is established if the platelet count is normal when repeated on a sample from heparin-anticoagulated or citrate-anticoagulated blood.
In patients who have risk factors for HIV infection, a blood sample should be tested with an enzyme immunoassay for anti-HIV antibodies.  During the acute HIV retroviral syndrome, the results of the anti-HIV assay may be negative. In this situation, a polymerase chain reaction for HIV DNA is more reliable than the anti-HIV assay.
In selected women, the medical history may suggest a chronic, recurrent, multisystemic illness with vague, generalized signs or symptoms, such as recurrent, multiple, painful, tender, or swollen joints. In such cases, a negative antinuclear antibody (ANA) result is useful in diagnosing ITP if the patient’s thrombocytopenia becomes chronic and resistant to treatment.
If anemia and thrombocytopenia are present, a positive direct antiglobulin (Coombs) test result may help establish a diagnosis of Evans syndrome.
In children with ITP who have already received their first dose of measles-mumps-rubella (MMR) vaccine, the American Society of Hematology recommends measuring vaccine titers. If the titers indicate full immunity (as is the case in up to 95% of children), then no further MMR vaccine should be given. If the titers indicate inadequate immunity, the child should receive further immunization with MMR vaccine at the recommended age. 
Assays for platelet antigen–specific antibodies, platelet-associated immunoglobulin, or other antiplatelet antibodies are available in some medical centers and certain mail-in reference laboratories. The reliability of the results of a platelet antibody test is highly specific to the laboratory used. A negative antiplatelet antibody assay result does not exclude the diagnosis of ITP.  The authors do not recommend this test as part of the routine evaluation. Testing for antiplatelet antibodies is not required to diagnose ITP.
Studies from Italy, [44, 45] Japan, [46, 47] and Korea  indicate that many persons with ITP have Helicobacter pylori gastric infections and that eradication of H pylori results in increased platelet counts. In the United States and Spain, however, the prevalence of H pylori infections does not appear to be increased in persons with ITP, and eradication of H pylori has not increased platelet counts. [49, 50] Therefore, routine testing for H pylori infections in adults and children with ITP is not recommended.
Results of a study from Taiwan suggest that ITP may be an early hematologic manifestation of HIV infection. Lai et al reported that patients with ITP were 6.47-fold more likely to have HIV infection than those without ITP, and recommended considering the possibility of undiagnosed HIV infection in patients presenting with ITP. 
Immune thrombocytopenia (THROM-bo-si-to-PE-ne-ah) or ITP is a rare autoimmune condition that can be as challenging to pronounce as it is to live with. Characterized by low blood platelet counts, you may hear ITP called by its original name of idiopathic thrombocytopenic purpura. Historically, “idiopathic” was used because the cause of the condition was unknown. Today we know ITP is caused by the body’s immune system destroying healthy platelets that leads to easy or excessive bruising and bleeding, in addition to initiating a daily roller coaster of emotions and ongoing medical management .
The Phases of ITP
Newly diagnosed ITP: within 3 months from diagnosis
Persistent ITP: 3 to 12 months from diagnosis.
Chronic ITP: lasting for more than 12 months
What causes ITP?
The specific cause behind why ITP develops is usually unknown and can differ from person to person. ITP has been shown to develop:
- After a viral or bacterial infection
- After certain immunizations
- After exposure to a toxin
- In association with another illness, such as lupus or HIV (human immunodeficiency virus)
While ITP can often seem mysterious as to why it occurs, the good news is that researchers continue to make progress in understanding the condition and its similarities to other autoimmune diseases. Learn more about the science behind the causes of ITP .
What are the symptoms of ITP?
The symptoms of ITP can vary greatly from person to person, and some with ITP may show no signs of having the condition. In general, the lower your platelet count, the more symptoms you may have including:
- Easy or excessive bruising (purpura)
- Petechiae (pe-TEEK-ee-ay), tiny red dots on the skin caused by broken blood vessels or leaks in a capillary wall
- Bleeding from the gums or nose
- Blood in urine or stools
- Unusually heavy menstrual flow
- Feeling tired or fatigued
How is ITP diagnosed?
ITP is a diagnosis of exclusion. Because there is no definitive test to diagnose ITP, your doctor will rule out other causes of low platelets, such as an underlying illness or medications you or your child may be taking. If no other cause is found, the diagnosis is often ITP.
In addition to asking about your or your child’s medical history, your doctor will perform a physical exam and run one or more of the following tests:
- Complete blood count (CBC): A common blood test used to determine the number of blood cells, including platelets, in a sample of blood.
- Blood smear: This test is used to confirm the number of platelets observed in a complete blood count.
- Bone marrow exam: If blood tests show your platelet count is low, a bone marrow test may be recommended to show whether your bone marrow is making enough platelets; the American Society of Hematology doesn’t recommend this test for children with ITP  .
What is the purpose of platelets?
Platelets are relatively small, disc-shaped cells circulating within your blood that bind together when recognizing damaged blood vessels. For example, when you get a cut, platelets bind to the site to cause a blood clot—and stop the bleeding. A normal platelet count is between 150,000 and 450,000 per microliter of blood. If someone has a platelet count lower than 100,000 per microliter of blood with no other reason for low platelets, they are considered to have ITP. And, because they have fewer platelets, people with ITP are more prone to prolonged bleeding. Learn more about the role and function of platelets in ITP here.
The Platelet Destruction Process
Ask the Experts Q&A
More videos with answers to common questions about ITP, symptoms, treatments, and daily life with ITP.
Finding out you have ITP can be shocking and confusing, changing your life over night. You may have never heard of the disease, and learning how the autoimmune condition can trigger excessive bruising and spontaneous episodes of bleeding that fuels ongoing fatigue and anxiety can be overwhelming.
Although a diagnosis of ITP is rare, you’re not alone. In fact, an estimated 50,000 people in the U.S. are currently living with and successfully managing the condition.
How many adults are affected?
It’s hard to determine how many adults have ITP. A recent study reports the incidence of adult ITP, or how many people are diagnosed each year, is 3.3 per 100,000 adults per year. 1 The prevalence of ITP in adults—those who have ITP at any time—is approximately 9.5 cases per 100,000.
ITP can strike at any age and affects more women than men ages 30 to 60. Yet, research shows men are equally affected in other age groups. 2
How do I know I have ITP?
ITP is difficult to diagnose, and is often called a “diagnosis of exclusion.” Because there is no definitive test to diagnose ITP, your doctor will first rule out other causes of low platelets, such as underlying illness or medications you may be taking. If no other cause is found, and after a complete medical history, physical exam and tests are completed, the diagnosis is often ITP.
How long does ITP last?
In adults, most cases of ITP are either persistent (lasting six to 12 months) or chronic (lasting more than a year). Fortunately, today’s treatments are able to increase your platelet count and restore your overall health. Yet, the right treatment may take time to find. By being patient and working with your doctor and healthcare team, you can start a successful routine to manage your condition.
How is ITP treated in Adults?
There is no one best way to treat ITP. Treatments should be tailored to you, not your platelet count. If you’re experiencing only mild bruising and petechiae (small red or purple dots), your doctor may want to only observe you for a while. If your symptoms are more severe, he or she may recommend prompt treatment to raise your platelet counts.
It’s important both you and your doctor carefully weigh the potential risks and benefits when making a treatment decision. Like any condition, communication is the key to successful treatment.
At PDSA, we know that strong social and emotional support is a powerful tool for those living with ITP. We’re dedicated to providing resources to educate and empower you, ease your anxiety and improve your overall health.
Register to Elevate Research for Answers
Learning more about PDSA’s ITP Natural History Study Registry is an important first step in helping advance ITP research. The next best step? Enrolling in PDSA’s national patient registry to advance the science needed to improve the quality of life for ITP patients.
In 2015, ASH initiated an effort to update the 2011 ASH guidelines on Immune Thrombocytopenia (ITP). ASH appointed thirteen clinical experts, two methodologists and two patient representatives to review evidence and form twenty-four recommendations on ITP. The recommendations address treatment of both adult and pediatric ITP. Development of these guidelines, including systematic evidence review, was supported by the University of Oklahoma Health Sciences Center.
Access the full guidelines on the Blood Advances website:
The ASH ITP guidelines have been endorsed by the following organization:
Learn more about the development process behind the ITP guidelines.
Guideline Implementation Tools and Resources
ASH Clinical Practice Guidelines App
The ASH Clinical Practice Guidelines App provides easy access to every recommendation from all guidelines published by ASH, including rationale for each recommendation, benefits and harms associated with each recommended course of action, and links to the complete evidence-to-decision tables used to develop the recommendations. This app is also available via web interface.
ASH Pocket Guides App
The ASH Pocket Guides App includes all of ASH’s pocket guides. This app is also available via web interface.
Printed versions of pocket guides are available for order on the ASH website, and at ASH meetings throughout the year. The following pocket guide is based on the – 2019 ASH Clinical Practice Guidelines for Management of ITP:
- Management of Immune Thrombocytopenia (ITP)
Help your colleagues diagnose, manage, and treat ITP with the following teaching slide designed for easy dissemination:
- Teaching slides for Immune Thrombocytopenia
Powerpoint | PDF
Listen to the Podcasts below to learn more about ASH’s ITP guidelines.
Table of Contents
What is idiopathic thrombocytopenic purpura (ITP)?
Idiopathic thrombocytopenic purpura (ITP) is a bleeding disorder. “Idiopathic” means the cause of the condition is unknown. “Thrombocytopenic” means the blood doesn’t have enough platelets. (Platelets are also called thrombocytes.) “Purpura” means a person has excessive bruising.
When you have ITP, your immune system destroys the platelets in your blood. Platelets are the tiny cells that form blood clots. They seal minor cuts and wounds. A person who doesn’t have enough platelets bruises very easily. They can bleed for a long time after being injured. A person who has ITP might have nosebleeds that are hard to stop. Rarely, they might have bleeding in the intestines, or even bleeding in the brain with minor trauma.
ITP is also sometimes called “immune thrombocytopenic purpura” or “immune thrombocytopenia.” It can happen in adults or children. In children, the condition usually resolves on its own without treatment. For adults, it is often a long-term condition.
Symptoms of ITP
The symptoms of ITP include:
- Easy or excessive bruising.
- Tiny reddish purple dots on the body, especially on the lower legs. Called petechial rash, this is caused by bleeding under the surface of the skin.
- Cuts or minor wounds that take a very long time to clot or stop bleeding.
- Blood in the urine or stools.
- Unusually heavy menstrual flow in women.
- Unexplained bleeding from the nose or gums.
In most adults, ITP lasts much longer than it does in children. At the time of diagnosis, many adults have noticed symptoms for several weeks or months. At the same time, many adults have only mild thrombocytopenia. Some have no bleeding symptoms at all.
What causes ITP?
The cause of ITP is not known. People who have ITP form antibodies that destroy their blood platelets. Normally, antibodies are a healthy response. They attack and destroy bacteria or viruses. But in people who have ITP, the antibodies attack the body’s own cells. Doctor’s aren’t sure exactly why this happens.
Who gets ITP?
There are 2 types of ITP—acute (short-term) and chronic (long-term). Acute ITP mainly affects children. They often get the condition after a viral illness, such as the flu. The usual age for a child getting ITP is 2 to 4 years of age. Chronic ITP typically affects adults. Most adults with ITP are young women, but it can occur in anyone. ITP does not seem to be hereditary (run in families). ITP is not contagious (you can’t “catch it” from someone else).
How is ITP diagnosed?
Your doctor will ask you questions about your health. He or she will do a physical exam. They may take a blood sample for testing. The test counts blood cells and platelets. Or they may look at the sample under a microscope. Your doctor may also want you to get a bone marrow exam. This can help rule out other possible causes of your symptoms.
Many adults find out they have ITP by accident. Their blood is checked for another reason and a low blood platelet count is found.
Can ITP be prevented or avoided?
Since there is no known cause, there is nothing that can prevent or avoid the condition.
Mild cases of ITP may not require treatment, just regular monitoring of platelet levels. More serious cases will require treatment.
Treatment of ITP in adults does not cure the disease. It is aimed at increasing the blood platelet count. Your doctor may recommend that you take prednisone for several weeks or months. Prednisone is a steroid that raises the level of your platelet count. As your count rises and reaches a safe level, your doctor may gradually decrease your medicine. However, when the medicine is stopped, your platelet count may decrease again.
Other treatments for ITP include other medicines. These include:
- Another kind of steroid called danazol.
- Medicines that suppress the immune system.
- Infusions of high-dose gamma globulin.
- Anti-RhD therapy for people with certain blood types.
If medicines don’t help enough, your doctor may recommend that your spleen be removed. The spleen makes most of the antibodies that destroy the blood platelets. It also destroys old or damaged blood cells. But removing the spleen permanently reduces your body’s ability to fight infection. Some people can have the ITP come back even after the spleen is removed. So this treatment is not done as often as it used to be.
How is ITP treated in children?
ITP in children is usually mild. It runs its course without the need for treatment. About 80% of children recover completely from ITP within about 6 months. When a child is diagnosed, many doctors recommend just watching the child carefully. However, some doctors recommend a short treatment with prednisone pills or gamma globulin infusions. These treatments will increase the platelet count more quickly. Both medicines have some side effects.
Understanding Platelet Count
Normal platelet count is in the range of 150,000 to 450,000. With ITP, the platelet count is less than 100,000. By the time significant bleeding occurs, your child may have a platelet count of less than 10,000. The lower the platelet count, the greater the risk of bleeding.
Platelets are essential for the formation of a blood clot. Blood clots consist of a mass of fibers and blood cells. Platelets travel to a damaged area and stick together to form a plug whenever a person is cut, for example. If there are not enough platelets, a clot cannot be formed, resulting in more bleeding.
Symptoms of ITP
Because platelets help stop bleeding, the symptoms of ITP are related to increased bleeding. However, each child may experience symptoms differently. Symptoms may include:
- Purpura: The purple color of the skin after blood has “leaked” under it. A bruise is blood under the skin. Children with ITP may have large bruises from no known trauma. Bruises can appear at the joints of elbows and knees just from movement.
- Petechia: Tiny red dots under the skin that are a result of very small bleeds.
- Bleedingin the mouth and/or in and around the gums
- Blood in the vomit, urine or stool
- Bleeding in the head: This is the most dangerous symptom of ITP. Head injury that occurs when there are not enough platelets to stop the bleeding can be life-threatening.
The symptoms of ITP may resemble other medical problems. Always consult your child’s doctor for a diagnosis. Learn more about how we diagnose ITP at Stanford.
What is immune thrombocytopenia purpura?
Immune thrombocytopenic purpura, or ITP, is a blood disorder in which the platelets drop well below normal levels. Platelets help blood to clot, and ITP can lead to excessive bleeding and bruising.
ITP usually occurs when the immune system mistakenly attacks and destroys blood platelets. If the cause of the immune reaction is unknown, the condition is called idiopathic thrombocytopenic purpura.
When children develop ITP, it’s usually from a viral illness and they generally recover fully without treatment. When adults get ITP, they usually have it longer and require treatment. In some cases, ITP can cause internal bleeding and be life threatening.
What causes ITP?
While ITP sometimes runs in families, it can also happen from other conditions that lead to a decline in platelets, such as viral infections, autoimmune disorders, blood cancers or bacterial infections.
What are the symptoms of ITP?
The symptoms of ITP depend on platelet levels, and some people with this condition have no symptoms. When platelet levels become low enough to cause symptoms, they can include:
- Bleeding from the nose or gums
- Blood in the urine or feces
- Blotches and bruises (called purpura)
- Heavier or longer periods during menstruation
- Red spots on the skin called petechiae. This usually occurs on the legs, feet, abdomen, buttocks and arms. Some people with ITP may have petechiae in their mouths.
How is ITP diagnosed?
The most common way to diagnose ITP is through blood tests to identify the number of platelets in the body. If the platelet count is below 150,000, ITP may be the diagnosis. Your doctor may also order:
- Bone marrow aspiration. Using a very fine needle, a doctor withdraws a sample of liquid bone marrow to check for cells that may not be working as they should.
- Bone marrow biopsy. Using a different type of needle, your doctor removes a sample of bone marrow tissue to review the number and types of cells within the bone marrow.
How is ITP treated?
Children with ITP typically don’t need treatment while adults usually do. Regardless of the person’s age, this condition should be treated if it is severe or persists.
There are a variety of treatment options to increase platelet counts, including oral and intravenous (IV) medicines.
ITP can also be treated with platelet transfusions and surgery to remove the spleen. This surgery will reduce the destruction of platelets, but also may raise your risk for infections.
Lifestyle changes can also help, such not using aspirin or ibuprofen, which can cause bleeding, and being careful to avoid injuries. It’s especially important to protect your head to avoid bleeding in the brain.
Can vaccines cause ITP?
Vaccines are essential for preventing many illnesses, and vaccine injuries are rare. However, vaccines against measles virus can sometimes cause ITP. It can take up to six weeks after the vaccination for symptoms of ITP to develop.
While this occurs in only one to three children for every 100,000 vaccine doses, the National Vaccine Injury Compensation Program (VICP) recognizes ITP as a vaccine injury in some cases.
Have you been injured?
If you or your child may have developed ITP from a measles or other vaccine covered under VICP, contact our vaccine injury attorneys today. We can file a claim for you with the VICP, at no cost to you.
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