[header] How to do the glass test [title] Identify a meningitis rash. [step] Rashes caused by meningococcal septicemia start as a scattering of small " pin prick " marks. These marks may appear reddish or brown and gradually develop into large patches of purple or red blotches and/or blood blisters. 
[substeps] Unlike most rashes, a rash caused by meningococcal septicemia will not fade or blanch when pressure is applied to it. The glass test makes use of this characteristic to help prove or disprove the source of such a rash.