Immune
Thrombocytopaenic Purpura

What is immune thrombocytopenic purpura?

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder. In ITP your body makes antibodies which are targeted against platelets. Once the antibodies have attached to platelets, the platelets do not work so well. They are also removed more quickly by the spleen because they are abnormal.

How common is ITP?

ITP occurs in about 3 in 100,000 adults every year. It is more common in women than in men between the ages of 30 and 60 years. At other ages, it is just as common in men as it is in women.

What are the symptoms?

In adults, ITP comes on gradually and does not usually follow a viral illness. It is not really known what causes the disease.

The symptoms may vary a lot. You may have no symptoms, purpura (rash under the skin due to bleeding), mild bruising or bleeding, or severe bleeding. Unlike ITP in children, most adults with ITP will continue to have a low number of platelets indefinitely. This is called chronic ITP.

How is ITP diagnosed?

Because most adults with ITP do not have any symptoms, ITP is usually diagnosed on a routine blood test that has been done for other reasons. The full blood count shows a lower number of platelets than normal. The laboratory will also look at your blood under a microscope. Sometimes a sample from your bone marrow may be necessary if you have an unusual presentation or if you fail to respond to initial treatment. Low platelet numbers can be due to other causes such as medication, viral infections or other diseases. It may be necessary for you to have some additional tests to rule out these other conditions.

What is the treatment?

Adults with ITP do not require treatment unless they have significant symptoms or if the platelet count is significantly reduced.It is also important to have adequate platelet levels before surgery or dental work, in order to reduce the risk of severe bleeding during the operation.

If treatment is needed then the first treatment that tends to be used in an adult with ITP is usually steroids. Sometimes steroids are used along with injections of IVIg (Intravenous Immunoglobulin).

Both of these treatments increase the platelet count in the majority of people. However, the platelet numbers may return to a low level after a few weeks.

If the above treatments do not work, there are several other options.

A medicine called rituximab has produced good responses. Romiplostim and eltrombopag are medicines which help you make more platelets and may be used if other treatments have not been helpful.

What if I am pregnant?

A low number of platelets in pregnancy is quite common. It can be difficult to know if your platelet count is low due to the pregnancy or due to ITP.
If you have no symptoms and the number of platelets is not too low, you may just be monitored. If the number of platelets needs to be increased then steroids or IVIg can be used.

What is the outlook?

In adults, the outlook (prognosis) is variable depending on the severity of symptoms. If treatment is needed, the response to treatment varies from person to person.