What Causes a Petechial Rash in a Child?

It is a rash with petechiae, which are red/purple spots that don't blanch on pressure - so when you push on them, you still see them.

The glass test is best for showing this - you press on the rash with a glass and you still see the rash through the glass even with pressure.

There are several photos on this page - the first shows the glass test.

The first photo at the bottom of the page shows a petechial rash and the second shows a more extensive rash that would be called purpuric.

You will notice that the rashes on this page are quite obvious. That is not always the case. Sometimes, there are just tiny pinprick red dots - the key to it being a petechial rash is that when you push on the spots/dots, they don't blanch (go white) - so you still see them when the glass is pressed on.

What is purpura?

Purpura (or a purpuric rash) refers to the same sort of rash as a petechial rash but the spots are often larger and it is more purple than red. So a child may have some small petechial spots and some larger areas of purpura.

What causes a petechial rash in a child?

There are many causes but some are serious and so if your child has a rash with petechiae, you need to seek urgent medical attention in case it is caused by a serious condition.

Serious causes of a petechial or purpuric rash include:

• meningococcal infection - the rash may start off as a blanching rash and your child may have fever. The rash can appear before your eyes. This is a very serious condition and can cause shock and death. Seek urgent medical attention
• idiopathic thrombocytopenia purpura - the rash is often more purpuric than petechial usually. Your child may just start off with large bruises that occur easily. The condition is caused by low platelets, which are the clotting cells in the blood. It usually resolves by itself over time, but sometimes treatment is required. See your doctor to confirm that this is the condition
• leukemia - this is a cancer of the bone marrow and causes low blood cells, including the clotting cells. Children may also be pale and prone to infection. Treatment is successful so see your doctor early
• severe infection - any infection if severe enough may interfere with the normal body clotting system and if your child is sick and has a petechial or purpuric rash, you need to seek urgent medical attention

Other causes of a petechial or purpuric rash include:

• viruses - particularly enterovirus infection
• Henoch-Schonlein Purpura - a condition that involves the skin, joints, gut and kidneys. It usually resolves by itself and no treatment is required but it is helpful to see a doctor to confirm the diagnosis
• pressure - such as tight clothing
• forceful vomiting or coughing - if this is the cause the rash is on the upper chest or face only

Can my child get meningococcal infection if she has been immunized?

There are several types of meningococcal infection and children are usually only immunized (vaccinated) against one type so it is possible for your child to get the infection if she is immunized.

Different countries immunize against different type of meningococcus depending on what one is the worst health problem for them.

If your child develops a petechial rash, take it seriously and seek medical attention urgently. It is better to be safe.