Immune thrombocytopenic purpura (ITP)

Background

The blood contains tiny cells called platelets, which help to prevent bruising and bleeding. If there are not enough platelets in your blood, cuts in your skin can carry on bleeding longer than usual, your gums can bleed when you clean your teeth and you can bruise without even being aware that you have knocked yourself. You may also develop little red dots on the skin. However, having low numbers of platelets is not the only cause of these symptoms.

Platelets are produced in the bone marrow and travel around in the circulation until they are needed at a site of injury (such as a cut or bang). If they are not needed in this way they normally survive for about 10 days before being removed from the bloodstream and replaced with new ones from the ‘platelet factory’ in the bone marrow.

What is ITP?

ITP stands for immune thrombocytopenic purpura. ITP is an acquired illness (you are not born with it) in which the body’s own immune system removes normal platelets from the bloodstream by mistake. The immune system usually protects you by finding, labelling and getting rid of things that don’t belong in your body – such as germs. In ITP the immune system mistakenly gets rid of your own platelets by attaching a special protein called an antibody to them so that they are attacked and destroyed.

Although you are making plenty of platelets, they are being ‘used up’ more quickly than usual and you become ‘thrombocytopenic’ which just means you have a low number of platelets. It is not known why the body begins to produce antibodies against its own platelets. It may be that an infection such as a cold or sore throat a few weeks beforehand may trigger the immune system to behave in this way.

The problems you may notice are bruises, also known as ‘purpura’, tiny red dots on the skin, known as ‘petechiae’, nose bleeds, and sometimes other bleeding such as gum bleeding when you clean your teeth. Girls can have heavy, prolonged periods.

A normal platelet count is between about 150 and 450 depending on age. Often people with ITP have platelet counts of less than 20 when they are first diagnosed with the condition. Experience has shown us that although there may be easy bruising, children with platelet counts around 20 rarely have any serious bleeding.

Important to remember

If there is any aspect about your child’s ITP that you would like to discuss further feel free to make an appointment with your consultant.

What are the symptoms to expect in ITP?

Most children seem perfectly normal, happy, active and well apart from the bruises and sometimes little red spots (petechiae) on the skin. These are caused by minute amounts of blood leaking out of the tiny blood vessels in the skin. The child will not have any pain or fever (high temperature) and will usually just be their normal selves. Some children may have nose bleeds which may take quite a while to stop, or they may have bleeding or ‘blood blisters’ in the mouth. Serious bleeding is almost never seen.

Is it very dangerous to have a low platelet count?

Although the numbers of platelets are reduced, the bone marrow is working hard supplying new platelets to replace the ones being removed by the immune system and the platelets that are present work very well. Although the symptoms described above can be alarming at first they are usually not dangerous and the safest thing to do once the correct diagnosis has been made is to just wait for the platelet count to recover on its own.

One important and serious problem that can occur very rarely is bleeding inside the head. This is called ‘intra cranial haemorrhage’. It is important to contact your hospital if your child has a head injury whilst their platelets are low so that they can be checked over and observed on a ward if necessary.

It is also important to contact a doctor if you feel your child is not themselves, with drowsiness, vomiting weakness or fits.

However this is very unusual, but it makes sense to be alert for these symptoms and to avoid activities where there is an obvious danger of a bad head injury until the platelet count begins to recover. Depending on the age of your child, these might include climbing frames, rollerblading, horse riding, contact sports, and so on. Individual activities can be discussed with your doctor.

Is ITP common?

ITP affects about 4 in every 100,000 children each year. We see between 8 and 10 new children with ITP each year at the Sheffield Children’s. It happens most frequently in both boys and girls aged between 2 and 6 years but any age can be affected.

How is the diagnosis made?

This is done by listening to your description of your child’s symptoms examining your child and taking a blood test to exclude other causes of low platelets. Occasionally if the platelet count is taking longer than usual to recover or if there are any symptoms that ‘don’t fit’ a bone marrow test is done. The reasons for this and the procedure itself would be explained fully by your doctor.

How do you treat ITP?

Mostly ITP just gets better on its own, so the most important thing to do is to reduce the risk of any serious bleeding whilst waiting for recovery to happen. Medicines such as ibuprofen and aspirin should be avoided as they stop the platelets working effectively. It is safe to use paracetamol if it is needed.

Intramuscular injections should be avoided – usually they can wait until the child has recovered, if not they can be given subcutaneously (just under the skin, not deep into the muscle). Activities should be restricted as described earlier and your child may temporarily need closer supervision, depending on their age. Any head injuries should be reported to the hospital. Your child can continue attending school or nursery as previously but the staff should be made aware of the information on this fact sheet.

You will be given a contact phone number to ring if you ever need advice or reassurance at any time of the day or night.

If there is no important bleeding we usually just wait for your child’s platelets to come back up to normal on their own. Minor mouth and nose bleeding can be helped by a medicine called tranexamic acid which makes any blood clots that do form stronger and less likely to dissolve away. It doesn’t have any effect on the platelet count itself.

If there is important bleeding, or your child needs an operation (for some unrelated condition) it may be necessary to actively treat the ITP (to raise the platelet count more quickly). This can be done with an intravenous infusion of a blood product called ‘immunoglobulin’ which would need a short stay in hospital, or it may be done with a short course of steroid medicine (prednisolone) taken by mouth, which can be done at home. Both these treatments have side effects and so are not used routinely. Very occasionally, when ITP has gone on for a long time (more than 12 months) and the symptoms are interfering with everyday life, other medications can be offered including thrombopoetin receptor agonists (eltrombopag or romiplostim) or rituximab.

Very occasionally if medications do not work an operation called a ‘splenectomy’ may help. Again this has some disadvantages and so is not used without careful consideration. However, if it is felt that your child would benefit from any of these treatments the advantages and disadvantages would be discussed with you fully beforehand.

How long does ITP last?

Most children have acute ITP which lasts for less than 3 months. In fact most are showing signs of recovery within 1 month and a few within 1 week.

Children who have platelets which remain low between 3 to 12 months have persistent ITP. There are some children (10 to 20 percent) who still have low platelets longer than 12 months after diagnosis – this is called chronic ITP. The chronic form is more common in girls and in older children but it is not possible to tell from the outset who will recover quickly and who will not.

A very few children make a full recovery but then their platelet count falls again weeks or months later, often following a viral infection, and then the platelets usually return to normal again. This can be repeated several times and is known as relapsing ITP.

80 to 90 percent of children (at least 8 out of 10) will have a normal platelet count a year after diagnosis without requiring treatment.

Can you catch ITP?

No. No one will catch ITP from your child and your child did not catch it from anyone.

What should I do if I’m worried?

At home watch your child for new bruises and bleeding. These should gradually improve and the old bruises and petechiae will completely disappear. If your child has a head injury or develops bleeding that will not stop with simple measures contact the haematology ward (ward 6) at Sheffield Children’s Hospital. Give your child’s name and diagnosis, explain what is happening and ask to speak to a member of the Haematology team.

Telephone number 0114 271 7309