Immune Thrombocytopenic Purpura (ITP)

What happens in ITP

Platelets are made in the bone marrow and normally live 7 to 10 days. In ITP, the immune system produces antibodies that coat platelets. The spleen recognizes the coated platelets and removes them early. The antibodies also interfere with the platelet-making cells (megakaryocytes) in the marrow, so production falls too.

The result is a low platelet count. Platelets that remain are often young, large and work well, which is why many people with ITP bleed less than their count would suggest.

Primary and secondary ITP

• Primary ITP: no other cause is found. This is the majority.
• Secondary ITP: caused by another condition, such as lupus, HIV, hepatitis C, H. pylori infection, chronic lymphocytic leukemia, some medicines, or occasionally after vaccines.

Phases

• Newly diagnosed: up to 3 months
• Persistent: 3 to 12 months
• Chronic: more than 12 months

Symptoms

• Easy bruising and large bruises from minor bumps
• Petechiae: tiny, flat, pinpoint red or purple dots, often on the lower legs, that do not fade when pressed
• Purpura: larger purple patches from bleeding under the skin
• Nosebleeds and bleeding gums
• Heavy or prolonged periods
• Blood blisters in the mouth ("wet purpura"), a sign of higher bleeding risk
• Blood in urine or stool
• Fatigue, reported by many adults even when bleeding is minor

Many people with mild ITP have no symptoms and are diagnosed after a routine blood test.

ITP in children vs adults

How ITP is diagnosed

ITP is a diagnosis of exclusion: there is no single test for it.

1. Complete blood count: an isolated low platelet count with normal red and white cells.
2. Blood smear: confirms the low count is real (not platelet clumping) and checks for abnormal cells.
3. Tests for secondary causes: HIV, hepatitis C, and in some cases H. pylori, thyroid tests, antinuclear antibodies, immunoglobulins, and a pregnancy test.
4. Bone marrow test: only when the picture is atypical, for example with other abnormal blood counts, weight loss, or failure to respond to treatment, or in older adults.

Other causes of low platelets that must be excluded include thrombotic thrombocytopenic purpura (TTP), leukemia, aplastic anemia, liver disease with an enlarged spleen, heparin, alcohol, and other medicines.

Treatment

The goal is a safe platelet count that prevents serious bleeding, not a normal count.

Observation

Children with mild bleeding, and adults with counts above about 30,000 and no significant bleeding, are often simply monitored.

First-line treatments

• Corticosteroids (prednisone or dexamethasone): raise platelets within days to weeks in most people. Courses are kept short, ideally 6 weeks or less, because of side effects.
• Intravenous immunoglobulin (IVIG): raises platelets quickly, within 1 to 3 days, for bleeding or before surgery. The effect lasts weeks.
• Anti-D immunoglobulin: for some Rh-positive people with a spleen.

Second-line treatments for persistent or chronic ITP

• Thrombopoietin receptor agonists (TPO-RAs): eltrombopag, romiplostim and avatrombopag stimulate the marrow to make more platelets. They work in most people and are taken long term.
• Rituximab: an antibody against B cells that produces lasting remission in some people.
• Fostamatinib and rilzabrutinib: oral drugs that reduce platelet destruction, used when other treatments have not worked.
• Splenectomy: removing the spleen gives long-term remission in about 2 in 3 adults. It is usually delayed at least 12 months to allow spontaneous remission, and requires vaccinations against encapsulated bacteria beforehand.

Emergency treatment

For life-threatening bleeding: platelet transfusion combined with IVIG and high-dose steroids, sometimes with tranexamic acid.

Living with ITP

• Avoid aspirin, ibuprofen, naproxen and other NSAIDs, which impair platelet function. Use acetaminophen (paracetamol) for pain instead.
• Check with your doctor before taking supplements that affect bleeding, such as fish oil, ginkgo and high-dose vitamin E.
• Avoid contact sports and activities with high head-injury risk when your count is low. Wear a helmet for cycling.
• Use a soft toothbrush and an electric razor.
• Tell dentists and surgeons you have ITP. Platelet targets of about 50,000 are typical for most procedures.
• Pregnancy: ITP can worsen in pregnancy. Plan care with your hematologist and obstetrician. Babies occasionally have low platelets at birth.

Outlook

Most children recover fully. In adults, ITP is often lifelong but usually manageable. Serious bleeding is uncommon, and bleeding in the brain is rare, mostly occurring with counts below 10,000 to 20,000. Many adults reach stable, safe counts with modern treatments.

Frequently asked questions

What platelet count is dangerous in ITP?

Serious bleeding is uncommon above 20,000 to 30,000 platelets per microliter. The risk rises below 10,000, especially with symptoms such as mouth blood blisters or nosebleeds. Doctors base treatment on bleeding symptoms as much as on the number.

Is ITP a form of cancer?

No. ITP is an autoimmune disorder, not cancer. It does not turn into leukemia. Because leukemia can also cause low platelets, doctors check the blood smear and sometimes the bone marrow to rule it out, particularly if other blood counts are abnormal.

What causes ITP in children?

ITP in children usually follows a viral infection, such as a cold, chickenpox or flu, by 1 to 3 weeks. The immune response to the virus mistakenly targets platelets. It often appears suddenly with bruising and petechiae in an otherwise well child, and most recover within months.

Can ITP go away on its own?

Yes, often in children: about two-thirds recover within 6 months and most within a year. In adults, spontaneous remission is less common but does occur, particularly in the first year. Chronic ITP can still be controlled well with treatment.

What should I avoid if I have ITP?

Avoid aspirin and NSAIDs such as ibuprofen and naproxen, heavy alcohol use, and supplements that thin the blood unless your doctor approves them. When your platelet count is low, avoid contact sports and activities with a high risk of head injury.