Immune thrombocytopenic purpura (ITP) is a blood disorder. With this disease, you have a lower amount of platelets than normal in your blood. Platelets are blood cell fragments that help with blood clotting. Having fewer platelets can cause easy bruising, bleeding gums, and internal bleeding. ITP is caused by an immune reaction against your own platelets. This means that your body's immune system attacks your platelets by mistake.

ITP is a rare autoimmune blood disorder that both children and adults can develop.

There are two forms of ITP:

• Acute thrombocytopenic purpura. This is the most common type of ITP and mainly affects younger children. Less commonly, it may occur in older children and adults. Symptoms often appear after a virus, such as chickenpox. Acute ITP often starts suddenly. Symptoms may go away in less than 6 months, usually within a few weeks. Treatment is often not needed. The disorder usually does not come back. Acute ITP is the most common form of the disorder.
• Chronic thrombocytopenic purpura. This disorder can happen at any age. Symptoms can last from 6 months to several years. Or they may last for your whole life. Adults have this type more often than children do, but it does affect teens. Females have it more often than males. Chronic ITP can go away and come back often. You must have ongoing follow-up care with a blood specialist (hematologist).

With ITP, your immune system attacks your body's own platelets by mistake. Most often, this is a result of antibody production against platelets. In a small number of cases, a type of white blood cell called T-cells will directly attack platelets. This immune system mistake may happen due to:

• Medicines (including over-the-counter medicines), which can cause an allergy that cross-reacts with platelets.
• Infections that set off the immune reaction that leads to ITP. These are often viral infections, including the viruses that cause chickenpox, hepatitis C, and AIDS.
• Pregnancy.
• Immune disorders, such as rheumatoid arthritis and lupus.
• Low-grade lymphomas and leukemias.

Sometimes the cause of ITP is not known.

A normal platelet count is about 150,000 to 450,000 per microliter (µL) of blood. With ITP, the platelet count is less than 100,000. By the time major bleeding occurs, you may have a platelet count of less than 10,000. The lower your platelet count, the greater your risk of bleeding.

Because platelets help stop bleeding, ITP symptoms are linked to increased bleeding. Each person's symptoms may vary depending on how low their platelet count is. Symptoms may include:

• Bruising or purple areas on the skin. These bruises (called purpura) are caused by bleeding under the skin. When you have ITP, bruises may occur for no known reason.
• Tiny red dots (petechiae) under the skin that are due to very small bleeds.
• Nosebleeds.
• Bleeding in your mouth, or in and around your gums.
• Heavy menstrual periods.
• Blood in your vomit, urine, or stool.
• Bleeding in your head. This symptom of ITP is the most dangerous. A head injury that occurs when you don't have enough platelets to stop the bleeding can be deadly.
• Feeling tired.

ITP symptoms may look like other health problems. Always see your doctor for a diagnosis.

Your doctor will take your health history and give you a physical exam. Your doctor may ask about any medicines you are taking that may cause bleeding or lower your platelet count. You may also have these tests:

• Complete blood count (CBC). This test checks the number of red blood cells, white blood cells, and platelets in your blood. With ITP, the red and white blood cell counts will be normal, but the platelet count will be low.
• Peripheral blood smear. This test is used as a follow-up test to an abnormal CBC. It checks different types of blood cells, in particular platelets for ITP.
• Other blood and urine tests. These tests are done to measure bleeding time and find possible infections.
• Bone marrow tests. This test determines whether your bone marrow is healthy and making enough platelets.

Treatment will depend on your symptoms, age, and general health. It will also depend on how severe the condition is.

When treatment is needed, the two most common forms of immediate treatment are steroids and intravenous immunoglobulin (IVIG):

• Corticosteroids. These medicines help prevent bleeding by slowing down platelet destruction. They can lead to a higher platelet count in 2 to 3 weeks. Side effects in long-term use may include weakened bones, diabetes, mood changes and depression, lower resistance to infection, weight gain, high blood pressure, and acne.
• Intravenous immunoglobulin (IVIG). IVIG is made of antibodies removed from blood donations from thousands of healthy donors. IVIG helps by increasing your platelet count. You may see a response in as little as 24 to 48 hours.

Other treatments for ITP may include:

• Rh immune globulin. This medicine briefly stops the spleen from destroying platelets. You must be Rh positive and have a spleen for this medicine to work.
• Medicine changes. If your doctor thinks a certain medicine is the cause, you may need to stop or change that medicine.
• Treating infection. If an infection is causing ITP, then treating the infection may help increase your platelet count.
• Surgery to remove the spleen (splenectomy). The spleen helps fight infections. When you have ITP, these antibodies destroy platelets by mistake. This surgery is done more often in people with chronic ITP to slow down platelet destruction.
• Platelet transfusion. This treatment may be needed if you have severe bleeding or are about to have surgery.
• Rituximab. This medicine is an antibody made in a lab. It slows the antiplatelet antibody production.
• Romiplostim, eltrombopag, and avatrombopag. These medicines stimulate the bone marrow to make more platelets.
• Fostamatinib. This medicine is used for the treatment of chronic ITP when the first treatment doesn't work. It blocks an enzyme to help prevent the immune system from destroying platelets. The platelet count goes up and the risk for severe bleeding goes down. This medicine is a pill.
• Lifestyle changes. These can include making sure that you use protective gear and not doing certain activities.

• ITP is a blood disorder. With this disease, you have a lower amount of platelets than normal in your blood.
• A decrease in platelets can result in easy bruising, bleeding gums, and internal bleeding.
• ITP may happen suddenly and go away in about 6 months (acute). Or it may be ongoing (chronic) and last for years.
• Treatment options include medicines that can reduce platelet destruction or help the body make more platelets.
• In some cases, surgery to remove the spleen is needed.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new directions your doctor gives you.
• Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions.