Another scarlet fever question - what other rashes look identical but are not strep?

[JessieBird]

The long story is in my other thread but in a nutshell, my baby appears to have scarlet fever. Doctor confirmed on visual inspection. His throat also shows signs of strep. But a 48hr culture came back negative. We think the test was probably faulty and did another swab today but have to turn over every stone - so what else could cause a rash that presents exactly as scarlet fever?

Thanks for indulging me...this community is priceless.