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. How do you tell the difference?

The Glass Test. How to tell if a rash is a non-blanching rash or a blanching rash.

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.

  1. Press glass over rash.
  2. If it disappears, it is blanching.
  3. If you can still see it, it is a non-blanching rash.

The glass test. A blanching rash. A blanching rash

The glass test. A blanching rash disappears when you press a glass on it.Press a glass against a blanching rash and it disappears, you can no longer see it

The glass test. A non-blanching rash looks the same as a blanching rash.A non-blanching rash

The Glass Test. You can still see a blanching rash when you press a glass over it.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.

See Also:

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.

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