Baby Tracker for DadsWhat is the glass test for a rash on a baby?
Press the side of a clear glass firmly against the rash, and if the rash does not fade under the glass, call 911, or your local emergency number, now. The NHS lists a rash that does not fade under a glass among the signs of meningitis, which is an emergency at any age.
Call 911 (or your local emergency number) now if your baby:
- The rash does not fade when a clear glass is pressed firmly on it, a sign of meningitis
| What you see | What it means | Action | Source |
|---|---|---|---|
| The rash does not fade when a clear glass is pressed firmly on it | A sign of meningitis | Call 911 now | NHS |
| The rash fades under the glass | Not this sign; the other signs on this site still apply | See the related questions | This page |
What the sources say
The rash does not fade if you press the side of a clear glass firmly against the skin.
On the NHS meningitis page this sentence is the caption under the photo of the rash.
At 3 AM
Use a clear drinking glass, not a cup you cannot see through. Press the side of the glass firmly over the spots and look at them through it. If the spots are still there under the glass, that is a rash that does not fade.
Do the test with the lights on. The dark-red night screen and a dim lamp hide colour, and a rash that is hard to see in the dark deserves a proper look.
A rash that fades is not this sign, but it does not clear the baby. The other emergency signs on this site stand on their own: colour, breathing, a baby you cannot wake, a seizure, and a fever in a baby under 3 months.
Have these ready: the baby's age in weeks, where the rash is, whether it fades under the glass, whether there is a fever, and whether the baby is feeding, waking and behaving as usual.
If there is time, photograph the rash with the glass pressed on it. A clinician would rather see it than hear it described, and the time stamp shows how fast it is changing.
Where the sources differ
The AAP pages in our source list do not describe the glass test, so this page rests on the NHS alone. We quote one page we have checked rather than add a second we have not.
You know your baby best. If you think something is seriously wrong, get help now.
This page is general information, not medical advice. If you're worried, call your pediatrician.
Related questions
Baby Tracker for Dads keeps this test and the other emergency signs on its free When to call a doctor page, with the same sources.