Immune Thrombocytopenia

Autoimmune thrombocytopenic purpura, Immune thrombocytopenic purpura, Idiopathic thrombocytopenic purpura, Werlhof disease, Autoimmune thrombocytopenia

Immune thrombocytopenia (ITP) is a rare blood disorder where the body’s own immune system mistakenly attacks and destroys platelets, the tiny cells that help blood clot. This can lead to unusual bruising, small red spots on the skin, and bleeding that’s harder to stop than normal.

Table of contents

• What is Immune Thrombocytopenia?
• How Common is ITP?
• Types of ITP
• What Causes ITP?
• Symptoms of ITP
• How is ITP Diagnosed?
• Treatment Options
• Living with ITP

What is Immune Thrombocytopenia?

Immune thrombocytopenia (ITP) is a disorder where your blood doesn’t clot as it should because you don’t have enough platelets, which are tiny blood cells needed for normal blood clotting. When you have ITP, your immune system makes antibodies (proteins that normally fight infections) that mistakenly identify your own platelets as foreign substances and attack them^[2]. This causes your platelet count to drop below normal levels.

When you are injured, platelets stick together to form a plug called a blood clot that seals your wound. When you have a low platelet count, you may have trouble stopping bleeding^[3]. The condition was once known as idiopathic thrombocytopenic purpura, and you may still hear healthcare providers use this older name^[1].

ITP is diagnosed when a person has isolated thrombocytopenia (a platelet count below 100,000 platelets per cubic millimeter of blood) without other causes or disorders that could explain the low count^[5]. A normal platelet count ranges from 150,000 to 450,000 platelets per cubic millimeter of blood^[8].

How Common is ITP?

ITP is a rare condition. Each year, about 4 in every 100,000 children and 3 in every 100,000 adults in the United States are diagnosed with this disorder^[2]. The incidence worldwide is approximately 3.3 cases per 100,000 people each year in adults^[11].

ITP is more common in women of childbearing age compared with men of the same age group. However, in older adults after age 60, the incidence is similar between men and women^[13].

Types of ITP

Healthcare providers classify ITP in two main ways: by what causes it and by how long it lasts.

Primary ITP occurs when your immune system attacks your platelets without any known underlying cause. About 80% of all ITP cases are primary ITP^[2]. Secondary ITP happens when you have other underlying conditions like chronic infections, blood cancers, or autoimmune disorders that affect your platelet levels^[2].

ITP is also classified by how long you have had the condition. Acute ITP usually goes away within three months and mainly affects children^[2]. In fact, about 80% of children with ITP have remission within one year^[11]. Persistent ITP lasts between three and 12 months. Chronic ITP lasts a year or more and mostly affects adults, with 70-80% of adults showing a chronic course^[11].

What Causes ITP?

The exact genetic cause of immune thrombocytopenia is unclear. ITP occurs when the body’s immune system malfunctions and attacks the body’s own tissues and organs, a process called autoimmunity^[5].

Normally, your immune system produces antibodies that attach to specific foreign particles and germs, marking them for destruction. In ITP, the immune system abnormally destroys platelets and makes fewer platelets than normal^[5]. When something damages or cuts your blood vessels, platelets swarm the damaged area, sticking together to form a clot that stops bleeding. With ITP, there aren’t enough platelets to do this job effectively^[2].

Some of the antibodies produced in ITP also affect cells in the bone marrow that produce platelets, known as megakaryocytes. This leads to a decrease in platelet production, further reducing the number of platelets in the blood^[5].

In some people with ITP, the abnormal immune reactions may coincide with an infection by certain viruses or bacteria. In children, ITP often happens after a minor infection, such as an upper respiratory infection^[5][1]. However, the relationship between the infection and ITP is not completely clear. Healthcare providers don’t fully understand why the immune system starts attacking platelets^[4].

Symptoms of ITP

Many people with ITP don’t have any symptoms at all^[1][2]. When symptoms do occur, they can develop slowly or quickly.

The most common symptoms of ITP include:

• Petechiae: Tiny red or purple dots that appear on your skin, especially on the lower legs. These look like a rash and are caused by bleeding under the skin^[1][2].
• Purpura: When petechiae join together, they form larger red, purple, or brownish-yellow spots on your skin. These spots are larger than petechiae but smaller than bruises^[2].
• Easy bruising: You may notice you’re developing bruises more easily than usual or have bruises you can’t explain^[1][2].
• Bleeding from the gums: You may notice blood on your toothbrush, and your gums may appear swollen^[2].
• Nosebleeds that may be heavy^[2][4].
• Blood in urine or stool: Your urine may turn pale pink, or your stool may appear very dark^[2].
• Heavy menstrual bleeding: Periods that last longer than seven days or bleeding more than usual^[2].
• Fatigue^[2][3].

You’re more likely to bleed the lower your platelet count drops. People who have very few platelets may experience heavy bleeding from their intestines or, in very rare instances, life-threatening bleeding inside the skull, called intracranial hemorrhage^[4][5].

In children, ITP symptoms might show up differently than in adults. Instead of saying they feel tired, children and teens might seem unusually cranky, emotional, or restless^[2].

If you or your child has symptoms that worry you, or if bleeding won’t stop, make an appointment with your healthcare provider. Uncontrolled bleeding is a medical emergency^[1].

How is ITP Diagnosed?

To diagnose immune thrombocytopenia, your healthcare provider will try to rule out other possible causes of bleeding and a low platelet count. There is no single test that can confirm ITP, making it a diagnosis of exclusion^[9][3].

Your provider will ask about your medical and family history and perform a physical examination^[3]. Blood tests are essential to check platelet levels and count the number of platelets in a sample of blood^[4][9]. Your healthcare team will also perform tests to look for other causes of a low platelet count^[4].

Rarely, adults might need a bone marrow biopsy to rule out other problems or to find out how well your body is producing platelets^[9][4]. In this procedure, doctors take a small sample of your bone marrow to examine.

Because corticosteroid treatment may change bone marrow appearance, if your healthcare provider plans to prescribe steroids, they may want to perform a bone marrow biopsy first if your clinical presentation or other findings are not typical for ITP^[12].

Treatment Options

Not everyone with ITP needs treatment. People with mild ITP who aren’t bleeding and whose platelet count isn’t too low might need only regular platelet checks^[1][3]. Children usually improve without treatment^[9].

Treatment is generally recommended when platelet counts fall below 20,000 to 30,000 per cubic millimeter in adult patients without symptoms^[11]. The goal of treatment is to increase the platelet count to a safe level, allowing patients to live normal lives while awaiting spontaneous or treatment-induced remission^[12].

Most adults with ITP will need treatment at some point, as the condition often gets worse or becomes chronic^[9]. Treatment options include:

Steroids (Corticosteroids): Healthcare providers often start with an oral corticosteroid, such as prednisone or high-dose dexamethasone. These medicines temporarily calm the immune system to slow the rate at which platelets are destroyed^[7][12]. When the platelet count returns to a safe level, your provider will tell you how to gradually reduce the dose. Long-term use of these medicines can increase the risk of infections, high blood sugar, and osteoporosis^[9].

Intravenous Immunoglobulin (IVIG): If corticosteroids don’t help or if you need a rapid increase in platelet count, your doctor may give you immune globulin through a vein^[9][12].

Anti-RhD Immunoglobulin: For people who are Rh(D)-positive and have their spleens intact, IV Rho immunoglobulin offers comparable effectiveness to IVIG, with less toxicity, easier administration, and lower cost^[12]. However, it may cause immune hemolysis (destruction of red blood cells)^[12].

Thrombopoietin Receptor Agonists (TPO-RAs): These medicines help your body make more platelets. They are second-line options for patients with ITP lasting three months or more and in those who depend on corticosteroids or don’t respond to them^[12].

Rituximab: This medicine slows down your immune system and is another second-line option^[12][13].

Fostamatinib: A spleen tyrosine kinase inhibitor that is a second-line option for adults with chronic ITP^[12].

Rilzabrutinib: A Bruton tyrosine kinase inhibitor, another second-line option for adults with chronic ITP^[12].

Splenectomy: Surgery to remove the spleen may be recommended if medications don’t work^[1][4]. Removing the spleen can help keep more platelets circulating in the blood because the spleen is a major site where antibody-coated platelets are destroyed^[4].

If you have life-threatening bleeding, doctors may give you a platelet transfusion, although these don’t usually work well in ITP because the antibodies in your blood attack the transfused platelets too^[4].

Your healthcare provider should discuss the pros and cons of treatment options with you. Some people find the side effects of treatment are worse than the disease itself^[9]. An optimized treatment strategy should aim at elevating platelet counts to a safe level with minimal toxicity and improving your health-related quality of life^[13].

Living with ITP

Living with ITP presents both physical and emotional challenges. Many people with ITP experience fatigue much of the time. There are several reasons for this, including iron deficiency and anemia (low red blood cell count)^[15][20]. Studies show that 50% to 90% of adults with ITP report experiencing fatigue^[2][8].

To boost your energy, you can:

• Eat a healthy diet with lean protein, whole grain carbohydrates, low-fat dairy products, fruits, and vegetables^[14]
• Drink plenty of water^[14]
• Get at least seven hours of sleep at night^[14]
• Exercise regularly with activities like swimming, stationary cycling, or yoga^[14]

One of the scariest aspects of having ITP is the possibility of uncontrolled bleeding, particularly from your nose or gums. To be prepared:

• Carry medications like aminocaproic acid or tranexamic acid that help prevent and reduce bleeding. Ask your doctor if these would be helpful for you^[15]
• Keep over-the-counter nosebleed treatments on hand^[15]
• Ask your nurse for a nosebleed treatment kit during your next medical visit^[14]

Make sure your healthcare provider knows about all medicines or supplements you take. You might need to stop using any that increase bleeding, such as aspirin, ibuprofen, or ginkgo biloba^[9].

It’s important to reduce stress in your life^[14]. Consider wearing medical alert jewelry so that emergency responders know about your condition^[15]. If you have a caregiver, remember that they need support too to avoid burnout^[15].

In adults, ITP is usually long-lasting, but in children, it often gets better on its own^[4]. Although ITP cannot be cured in many cases, with proper treatment and monitoring, most people with the condition can lead relatively normal lives.