Allergy? Post viral? Who can help with this rash...

[oldbirdy]

12 year old has a rash on his torso and neck. Slightly raised, mildly itchy. He used to get post viral rashes like this as a toddler but hasn't been ill - not even a cold. He has sensitive skin and gets eczema in his arm crooks and behind knees if we use highly scented washing powder, conditioner etc.
What do you think, mumsnet, could it be an allergy to his new lynx shower gel (used Sun eve) or maybe a rash from a virus that we didn't even notice? Pic of his chest and shoulder.

[oldbirdy]

Hopeful bump...

[Witchend]

Has he got a sore throat?

It does look a bit like scarlet fever to me? Does it feel like sandpaper?

When mine had Scarlet fever they weren't really ill at all, I only knew it was because I knew they'd been in contact.

[oldbirdy]

just asked him, he says no, not even slightly...

[oldbirdy]

It doesn't feel sandpapery, just a bit bumpy and slighty raised