Diseases & Conditions

Idiopathic thromobocytopenic purpura (ITP)

Idiopathic thrombocytopenic purpura (ITP), also called immune thrombocytopenic purpura, is a blood-clotting disorder that can lead to easy or excessive bruising and bleeding. ITP results from unusually low levels of platelets — the cells that help your blood clot.

Idiopathic thrombocytopenic purpura affects both children and adults. Children often develop idiopathic thrombocytopenic purpura after a viral infection and usually recover fully without treatment. In adults, however, the disorder is often chronic.

Treatment of idiopathic thrombocytopenic purpura depends on your symptoms and platelet count. If you don't have signs of bleeding and your platelet count isn't too low, treatment for idiopathic thrombocytopenic purpura usually isn't necessary. More serious cases may be treated with medications or, in critical situations, with surgery.

Some people with a low platelet count have no symptoms. When signs and symptoms do occur, they may include:

• Easy or excessive bruising (purpura) — your skin naturally bruises and bleeds more easily as you age, but this shouldn't be confused with ITP
• Superficial bleeding into your skin that appears as a rash of pinpoint-sized reddish-purple spots (petechiae), usually on your lower legs
• Prolonged bleeding from cuts
• Spontaneous bleeding from your gums or nose
• Blood in urine or stools
• Unusually heavy menstrual flows
• Profuse bleeding during surgery

When to see a doctor
If you or your child has abnormal bleeding or bruising, or develops a rash of pinpoint-sized red spots, see your doctor. It's also important to seek medical advice if you're a woman and suddenly develop increased menstrual bleeding.

Serious or widespread bleeding indicates an emergency and requires immediate care.

The exact cause of ITP isn't known. For that reason it's referred to as idiopathic — meaning "of unknown cause." It is known, however, that in people with idiopathic thrombocytopenic purpura, the immune system malfunctions and begins attacking platelets as if they were foreign substances.

Antibodies produced by your immune system attach themselves to the platelets, marking the platelets for destruction. The spleen, which helps your body fight infection, recognizes the antibodies and removes the platelets from your system. The result of this case of mistaken identity is a lower number of platelets than normal.

Ordinarily, you have anywhere from 150,000 to 450,000 platelets per microliter of circulating blood. As the number of platelets decreases, your risk of bleeding increases. The greatest risk is when your platelet count falls very low — below 10,000 platelets per microliter. At this point, internal bleeding may occur despite a lack of any injury, although this is rare.

In most children with ITP, the disorder follows a viral illness, such as the mumps or the flu. It may be that an infection sets off the immune system, triggering it to malfunction. But ITP in adults isn't linked to infections.

The biggest risk associated with idiopathic thrombocytopenic purpura is bleeding, especially bleeding into the brain (intracranial hemorrhage), which can be fatal. Major bleeding is rare with ITP, however. Complications are more likely to arise from the treatments — corticosteroids and surgery — used for chronic or severe ITP. In fact, many therapies pose more serious potential risks than does the disease.

Long-term use of corticosteroids can cause serious side effects, including osteoporosis, cataracts, loss of muscle mass and increased risk of infection. Removal of your spleen (splenectomy), which may be performed if corticosteroids aren't working, also makes you permanently more vulnerable to infection, although the risk of an overwhelming infection in a healthy person who has had a splenectomy is small.

Pregnancy
Pregnant women with mild ITP usually have a normal pregnancy and delivery, though antibodies to platelets can cross the placenta and affect the baby's platelet count. In some cases, a baby may be born with a low number of platelets. If this happens, your baby's doctor will want to monitor your child for several days. It's likely that your baby's platelet count will improve without treatment, but if the count is very low, treatment can help speed recovery.

If you're pregnant and your platelet count is very low or you have bleeding, you have a greater risk of heavy bleeding during delivery. In such cases, you and your doctor may discuss treatment to maintain a stable platelet count, taking into account the effects on your baby.