ITP stands for immune (sometimes idiopathic, meaning an unknown cause) thrombocytopenia purpura.
- Immune — because some children develop ITP after an illness and it has been suggested that the body produces antibodies that attack platelets following the infection although this is unknown for sure.
- Thrombocytopenia — refers to low platelets. Platelets are the smallest of the blood cells and work to form a plug whenever a blood vessel is injured.
- Purpura — small purple spots that appear on the skin and mucous membranes.
ITP occurs in four out of 100,000 children and the peak age is between 2- to 5-years-old. It occurs in boys and girls at the same rate. The vast majority of children with ITP do not experience any serious complications and recover fully.
About 85% of children who get ITP will recover within six months. We call this acute ITP. The other 15% of children will have the disorder longer and are classified as having chronic ITP.
What Causes ITP?
There is no clear cause for the disorder, but it may be preceded by an infection. There are many cases, however, where the cause is unknown. Other causes include medications, for example, certain antibiotics and seizure medications, or it can be caused by immune disorders such as lupus.
The condition is not contagious. The body begins to form antibodies to platelets and destroy them, causing the symptoms that are seen in ITP.
ITP can be diagnosed in most cases with just a CBC, or complete blood count. The other blood cell counts are normal (white blood cells, red blood cells). A physical exam is performed to look for bleeding and purpura. There is no specific test for ITP. Only in rare situations is a bone marrow sample needed.
What Are the Symptoms of ITP?
In mild cases of ITP, there may be scattered purpura, or small purple spots on the skin. This may progress to increased bruising (not usually associated with trauma), and nosebleeds. In rare cases, bleeding can occur in the gastrointestinal tract, urinary tract and in the brain.
How Is ITP Treated?
A large number of cases of ITP resolve on their own without treatment. Treatment is generally given when the platelet count is at a very low level (around 10,000), or when there is significant bleeding. There are several drugs that can be used for ITP. The most common first-line drugs are steroids, intravenous immunoglobulin (IVIG) or an anti-D immunoglobulin medication such as WinRho. Steroids help prevent the body from making antibodies to platelets. IVIG helps to protect the antibody-coated platelets from destruction by the spleen. The anti-D immunoglobulin is given to children who have an Rh+ blood type; it works by also protecting the antibody-coated platelets from destruction by the spleen.
Other drugs can be used in children who do not respond to the previous drugs. Rituximab helps to suppress the immune system, preventing the production of antibodies. In some cases, the spleen must be removed, but it is usually reserved for patients who do not respond to any therapy and are at increased risk for bleeding.
You should call a doctor when the following occur:
- Increased bruising or purpura
- Nosebleeds that last longer than 15 minutes despite measures to stop it
- Generalized bleeding
- Onset of a severe headache or vomiting
- Blood in the vomit, stool or urine
Work with your hematologist and hematology nurse to find out if your child needs any activity restrictions when the platelet count is low. Generally, activity restrictions begin once the platelet count drops below 50,000.