Everything You Need to Know About Immune Thrombocytopenia

Immune thrombocytopenia (also called immune thrombocytopenic purpura or ITP) is an autoimmune disorder that causes low platelet levels (thrombocytopenia). Platelets are a type of blood cell that stop bleeding. When skin is wounded, platelets stick together to form a clot. 

Usually adults have anywhere from 150,000 to 450,000 platelets per cubic millimeter. But in ITP, numbers are less than 100,000 — and sometimes as low as 1,000. And when platelets are low, it’s harder for the body to stop bleeding. 

ITP is not very common. It occurs in about 10 in 100,000 people. ITP can affect both children and adults, and it affects women more than men. In this article, we discuss the causes, symptoms, diagnosis, and treatment of ITP. 

What causes immune thrombocytopenia?

Many conditions can cause low platelet levels. When it comes to ITP, the cause is autoimmune.  The immune system is the body’s army. It helps protect against things that don’t belong, like infections. But sometimes it gets confused and attacks your own body instead (“auto” means “self”). In ITP, the immune system accidentally attacks your own platelets. 

ITP can occur by itself — primary ITP. Or it can be due to something else. Secondary causes of ITP include:

• Medications 

• Other autoimmune diseases (like lupus)

• Pregnancy

• Infections (like hepatitis C, HIV, or H. pylori)

• Blood cancers (like lymphoma or leukemia) 

• Immunodeficiency syndromes (conditions in which the immune system is weaker than normal)

• Evans syndrome (which causes both low platelets and low red blood cells)

• Vaccine side effects

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What are the symptoms of immune thrombocytopenia?

Signs and symptoms of ITP depend on how low the platelet count is. If platelets are only slightly below 100,000, there may be no signs at all. But, the lower the platelet count, the more severe the signs. 

ITP can cause:

• Bruises or petechiae (red, purple, or brown dots caused by tiny broken blood vessels in the skin)

• Prolonged bleeding when skin is injured

• Nosebleeds

• Heavier or longer periods

• Bleeding gums, especially when brushing your teeth

• Blood in urine or stool

• Extreme fatigue

ITP can also cause wet purpura, or purple spots inside of the mouth or on the tongue. If you have wet purpura, seek care in an emergency room as soon as possible. This only occurs when platelet counts are dangerously low (less than 10,000).

ITP can also cause bleeding that is difficult to stop. Fortunately, only 5% of people have severe bleeding at diagnosis. But when platelets are dangerously low, life-threatening bleeding can occur. For example, bleeding into the brain can be fatal. If you develop a new, severe headache or symptoms of stroke, call your provider and go to the nearest emergency room.

How do you diagnose immune thrombocytopenia?

To diagnose ITP, platelet counts must be lower than 100,000. Then your healthcare provider must rule out other causes of low platelets. They’ll usually do this with additional blood tests.  

To measure platelet counts, your provider will order a specific blood test — a complete blood count with differential (“CBC with diff”). Since you may not have symptoms with a low platelet count, sometimes a routine blood test picks it up.

Most of the time there’s no need for a bone marrow biopsy to diagnose ITP. Bone marrow is inside the bones where new blood cells are made. The procedure to look at your bone marrow is invasive, so your provider will only recommend it if they suspect some other diagnosis (like blood cancer). It might also be necessary if someone with ITP isn’t getting better with standard therapies. 

How do you treat immune thrombocytopenia?

Not everyone with ITP needs treatment. If platelet counts are mildly low, the risk of bleeding is also low. So watching and waiting might be best. 

If your provider recommends treatment, it will depend on a few different factors, like your age and the underlying cause. The overall goal is to prevent severe and potentially deadly bleeding.

When ITP is secondary to something else, the first step is to treat the cause. For example, if a medication causes ITP, you’ll stop the medication. And if an infection causes ITP, you’ll need to treat the infection. Platelets might improve with these changes alone.

In the case that you need medication, there are several options:

• Steroids: These are the first options for children and adults, since they’re cheap and effective. Prednisone is a common example. But platelet counts may drop when you stop taking steroids, and continuing them forever isn’t a great option due to side effects. 

• Intravenous immunoglobulin (IVIG): These are normal antibodies pooled from healthy donors. You might use IVIG alone or along with steroids.

• Immunosuppressants: These turn off parts of the overactive immune system to stop platelet destruction. Examples include fostamatinib and rituximab.

• Thrombopoetin receptor agonists: These help the body make more platelets. Examples include romiplostim and eltrombopag.

• Splenectomy: This surgery removes the spleen — the organ that destroys platelets tagged by antibodies. It’s a high-risk procedure, so surgeons only perform it when all else has failed. 

When someone has life-threateningly low platelet counts, they’ll need platelet transfusions (similar to blood transfusions) to increase counts to safe levels. But the effect is only temporary because the immune system will continue to destroy them. That’s why it’s so important to treat the underlying cause. 

When it comes to numbers, the goal is to keep platelets above 20,000 to 30,000. The risk of major bleeding increases when platelets are below this range. When platelets fall below 10,000, life-threatening bleeds can occur.

What else can you do to prevent bleeding?

In addition to the above treatments, here are some other things you can do to prevent bleeding:

• Avoid contact sports (like football and martial arts).

• Review your medication list with your provider to get rid of those that increase bleeding risk (like aspirin, warfarin, or clopidogrel).

• Avoid taking nonsteroidal anti-inflammatory drugs, like ibuprofen (Advil, Motrin) and naproxen (Aleve) for pain. Try acetaminophen (Tylenol) instead — it doesn’t increase bleeding risk.

What foods should you avoid with immune thrombocytopenia?

There are no specific foods to avoid with ITP. There is currently no scientific evidence that any foods increase or decrease platelet counts.

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Written by:

Samantha C. Shapiro, MD

Samantha Shapiro, MD, is a board-certified rheumatologist and internist with expertise in autoimmune and inflammatory conditions. She founded the division of rheumatology at Dell Medical School at The University of Texas at Austin.

Edited by:

Mandy Armitage, MD

Mandy Armitage, MD, has combined her interests in clinical medicine with her passion for education and content development for many years. She served as medical director for the health technology companies HealthLoop (now Get Well) and Doximity.

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