ITP (low platelets): Full guide

What is ITP?

ITP stands for immune thrombocytopenia. Thrombocytopenia means a low number of platelets in the blood. Platelets are tiny blood cells that help your blood clot and stop bleeding.

In ITP, your immune system makes antibodies by mistake that attack your own platelets. Antibodies are proteins that normally fight germs. The spleen, an organ on the upper left side of your belly, then removes these marked platelets. The immune system can also slow down how many platelets your bone marrow makes.

ITP is not cancer, and it is not contagious. It is an autoimmune condition, which means the immune system is acting against the body.

In children, ITP often follows a virus and usually goes away on its own within weeks to months. In adults, it more often lasts longer than a year. Even then, many adults have only mild symptoms or none at all.

There is no single test that proves ITP. Doctors diagnose it by finding low platelets and ruling out other causes. The goal of treatment is to prevent serious bleeding, not to reach a perfectly normal platelet count.

Types and phases

Newly diagnosed ITP

The first 3 months after diagnosis. In children, most cases get better during this time. Adults may also improve, but it is less common.

Persistent ITP

ITP that lasts from 3 to 12 months. Some people still go into remission (the condition goes away) during this time.

Chronic ITP

ITP that lasts longer than 12 months. This is the most common pattern in adults. It is a long-term condition that is managed, often with good control.

Primary ITP

ITP with no other cause found. This is the most common kind.

Secondary ITP

ITP caused by another condition, such as hepatitis C, HIV, H. pylori stomach infection, lupus, or some blood cancers. Treating that condition can help the platelets recover.

ITP in pregnancy

ITP can start or get worse during pregnancy. It needs a team approach with your obstetrician and hematologist. A milder, common condition called gestational thrombocytopenia also lowers platelets in pregnancy but is not ITP and usually needs no treatment.

Evans syndrome

A rare condition where the immune system attacks both platelets and red blood cells. It needs treatment for both problems.

Refractory ITP

ITP that has not responded well to several treatments. There are still many options, and specialists can help.

Tests you may have

Complete blood count (CBC)

A blood test that counts your platelets, red blood cells, and white blood cells. In ITP, usually only the platelets are low.

Blood smear

A drop of your blood is looked at under a microscope. This confirms the platelets are truly low and checks for signs of other conditions.

Repeat count in a different tube

Sometimes platelets clump together in the test tube and the machine counts too few. This is called pseudothrombocytopenia. Repeating the test in a different tube can show the count is actually normal.

Hepatitis C and HIV tests

These infections can cause low platelets. Testing is advised for all adults with ITP, because treating the infection can help.

Hepatitis B test

Checked before treatment with rituximab, because rituximab can wake up a hidden hepatitis B infection.

H. pylori test

A breath or stool test for a stomach germ. Treating it can raise platelets in some people, especially those from areas where the germ is common.

Other blood tests

Your care team may check liver and kidney function, thyroid, antibody levels, and tests for lupus. These look for other causes of low platelets.

Bone marrow biopsy

A needle takes a small sample of marrow from the back of the hip bone, after numbing medicine. It is not needed for most people with ITP. It may be done if other blood counts are low or the spleen is large. It may also be done if the smear looks unusual or treatment is not working.

How serious it is

How serious ITP is depends mostly on bleeding, not just on the platelet number. Two people with the same count can have very different symptoms.

Serious spontaneous bleeding (bleeding without an injury) usually does not happen until platelets are very low. Bleeding in the brain is rare. Your age, other health problems, blood thinners, and planned procedures all affect your risk.

Mild: no or minor bleeding

Some bruising or tiny red spots on the skin. Many adults with platelets above about 30,000 and no bleeding can simply be watched without treatment.

Moderate: more bleeding

Nosebleeds, bleeding gums, or heavy periods. Treatment is often started, especially if platelets are under about 30,000.

Severe: serious bleeding

Examples are bleeding in the stomach or bowel, coughing up blood, or blood in the urine that does not stop. Any bleeding in the head is severe. This is an emergency and needs treatment right away, often in the hospital.

Before surgery or procedures

Most procedures need platelets of at least about 50,000. Some, like spinal anesthesia, eye surgery, or brain surgery, need higher counts. Your care team can raise your platelets before a planned procedure.

Blood thinners and aspirin

You may also need a blood thinner or aspirin. If so, your care team will balance bleeding and clot risk. They may aim for a higher platelet count.

Lab tests to know

Your platelet count is the main number used to follow ITP. It can change from week to week. Your care team looks at the trend and at your bleeding symptoms, not just one result.

Platelet count

Normal is about 150,000 to 450,000 per microliter of blood. In ITP it is below 100,000. Doctors often write it in short form, like 30K for 30,000.

Hemoglobin

Usually normal in ITP. A low value can mean you have been losing blood, or that there is another problem such as Evans syndrome.

White blood cell count

Usually normal in ITP. If it is abnormal, your care team will look for other causes.

Response to treatment

A response usually means platelets have risen to at least 30,000 and doubled, with no bleeding. A complete response means 100,000 or more.

Liver tests

Some ITP medicines, like eltrombopag and fostamatinib, can affect the liver. You will have regular liver blood tests while taking them.

Antibody (immunoglobulin) levels

Low antibody levels can point to an immune problem that can look like ITP. They may also be checked after rituximab.

Platelet antibody tests

Tests that look for antibodies on platelets are not usually helpful. A negative result does not rule out ITP.

Main treatments

Watching closely

Many adults with mild ITP and no bleeding do not need treatment. You get regular platelet checks instead. Most children with no or minor bleeding are watched too.

Steroids

Steroids such as prednisone or dexamethasone calm the immune system. They are usually the first treatment. Platelets often rise within days. They are given for a short time only, usually no more than 6 weeks, because of side effects with long use.

IVIG (intravenous immune globulin)

An infusion of antibodies collected from donated blood. It raises platelets quickly, often within 1 to 2 days, but the effect wears off in a few weeks. It is useful for bleeding or before surgery.

Anti-D immune globulin

An infusion for some people with Rh-positive blood who still have their spleen. It works quickly. It breaks down some red blood cells on purpose, so you will be watched for serious breakdown.

TPO medicines (thrombopoietin receptor agonists)

These medicines tell your bone marrow to make more platelets. Romiplostim is a weekly shot. Eltrombopag is a daily pill taken away from food and calcium. Avatrombopag is a daily pill taken with food. They work for most people while they take them. Some people can slowly stop and keep a good count. They are often the preferred next step after steroids.

Rituximab

An antibody given by IV, usually once a week for 4 weeks. It lowers the immune cells that make the platelet antibodies. About half or more of people respond, but long-lasting remission happens in a smaller group. It avoids surgery and daily medicine.

Splenectomy (removing the spleen)

Surgery to remove the spleen, where most platelets are destroyed. It works in most people, and many have a lasting response. It is usually delayed at least a year, because ITP can get better on its own. You need special vaccines before surgery and must take fevers seriously for life.

Fostamatinib and rilzabrutinib

Newer pills for adults whose ITP did not respond well enough to earlier treatment. Fostamatinib (Tavalisse) blocks a signal the spleen uses to destroy platelets. Rilzabrutinib (Wayrilz) was approved in 2025 and blocks a different immune signal called BTK.

Other immune-calming medicines

Older medicines such as mycophenolate, azathioprine, cyclosporine, danazol, and dapsone are sometimes used when other treatments have not worked. Some are not safe in pregnancy.

Emergency treatment for serious bleeding

For dangerous bleeding, several treatments are given together in the hospital. These often include IV steroids, IVIG, platelet transfusions, and a medicine called tranexamic acid that helps clots hold.

Treatment side effects and what helps

Steroid side effects

Trouble sleeping, mood changes, more hunger, weight gain, high blood sugar, and stomach upset. Taking them in the morning with food can help. Tell your care team if you have diabetes, because your sugar may need closer checks.

Headache and reactions from IVIG

Headache, chills, and feeling achy are common during or after IVIG. Drinking fluids and going slowly can help. Rarely, IVIG can cause blood clots, kidney problems, or a severe headache with stiff neck. Call if a headache is severe.

Red blood cell breakdown from anti-D

Anti-D can break down red blood cells, sometimes seriously. Call right away if you have dark or red urine, back pain, chills, or yellow skin after treatment.

Blood clots from TPO medicines

These medicines can slightly raise the risk of blood clots. Your care team watches your platelet count so it does not get too high. Report leg swelling or sudden shortness of breath.

Liver effects

Eltrombopag and fostamatinib can affect the liver. You will have regular blood tests. Tell your care team about yellow skin or eyes or dark urine.

Platelet drop after stopping a TPO medicine

Platelets can fall quickly, sometimes lower than before, if a TPO medicine is stopped suddenly. Do not stop on your own. Your care team will lower it slowly if needed.

Infections and infusion reactions from rituximab

Rituximab can cause chills, fever, or rash during the infusion, and raise the risk of infections for months. Ask about vaccines before you start.

Diarrhea and high blood pressure from fostamatinib

Diarrhea is common. High blood pressure and liver changes can also happen. Your care team may change the dose. Check your blood pressure as advised.

Infection risk after splenectomy

Without a spleen, some bacterial infections can become serious very quickly. Get all recommended vaccines and boosters. Treat any fever as an emergency. Your care team may give you antibiotics to keep at home.

Living with ITP

Most people with ITP live full, active lives. Many adults have long periods with a safe platelet count, with or without treatment. The aim is to keep you safe from serious bleeding with as few side effects as possible.

Learn your usual platelet count and how you tend to bleed. Keep a list of your treatments and your care team's phone number with you. Wear a medical alert bracelet if your platelets are often very low.

Avoid medicines that affect platelets, such as aspirin, ibuprofen, and naproxen, unless your care team says they are okay. Acetaminophen is usually a safer choice for pain. Check with your care team before taking herbal supplements, such as fish oil, ginkgo, or high-dose vitamin E.

Stay active, but avoid contact sports or activities with a high risk of head injury when your count is low. Use a soft toothbrush and an electric razor. Ask your care team what activities are safe for your count.

If you are pregnant or planning pregnancy, talk with your hematologist and obstetrician early. Most women with ITP have healthy pregnancies. Some medicines must be changed, and the baby's platelets should be checked after birth.

People with ITP can also get blood clots, so do not ignore leg swelling or sudden shortness of breath. Living with a long-term condition can be stressful. Support groups, such as the Platelet Disorder Support Association, can connect you with others who understand.