Blanching and Non-Blanching Rashes
Rashes in Children can be divided into 'blanching' and 'non-blanching'. The group called 'blanching' disappears when you press it. The group called 'non-blanching' doesn't disappear when you press it. A 'petechial' rash is a non-blanching rash that is very small, like pin pricks. They both look the same. How do you tell the difference?
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The Glass Test
The way to tell if a rash is blanching or non-blanching is to place a clear drinking glass over the rash and press down. You can see that both the blanching and the non-blanching rash look exactly the same without the glass.
- Press glass over rash.
- If it disappears, it is blanching.
- If you can still see it, it is a non-blanching rash.
Press a glass against a blanching rash and it disappears, you can no longer see it
A non-blanching rash
Press a glass against a non-blanching rash and it doesn't disappear, you can still see it
Some non-blanching rashes are not serious. For example, many children get little spots around their eyes when they vomit.
However, a non-blanching rash may be a sign of serious illness so it is worth getting it checked out by your doctor.
Signs of Serious Illness in Children and Babies. How to tell if an illness is more than just a common cold.
Rashes. A guide to what to do when your child has a rash.