Allergy/rash advice please

[xQuinnx]

Hi my daughter is 9 months old nd isn't too well at the moment and I'm feeling a bit lost.
On Thursday she had a temperature of 38degrees, by Friday afternoon (less then 24 hours later) the temperature was gone and a light rash appeared. She went off food completely, was super cranky and tired (although that might be because my husband kept waking her up early from naps!) on Friday night however her appetite went back to normal and she woke up on Saturday morning her usual self however the rash was much worse. The rash was on her stomach and back at first but then spread to behind her ears, it looked kind of like a roseola rash. We took her to a pharmacist and they weren't concerned. She ate normally, no temperature until that night when she refused her last bottle and was really unsettled, the rash had spread to her face and her eyes were red underneath. Took her to urgent care and they said the rash was nothing to worry about, was possibly viral but most likely an allergic reaction and they gave us pyriton.

After that long ramble my questions are this: what could cause this type of allergic reaction if that's what it is? We haven't changed anything, been anywhere different, introduced anything new. She does go to a childminder so could be something there possibly I spose. Also would an allergy cause a child to become that unhappy and unsettled? Why was there a fever at the start if it was an allergy?!
I'm just worried something more might be going on :/

 

[Cattia]

It's not all that uncommon for them to get a viral rash. It's just the immune system reacting to a virus and goes away on its own. I know my DS had this a couple of times when he was a baby. If it was a reaction to something she had eaten I would say she was less likely to have had the temperature with it.

ETA what I was trying to say was it can be an allergic reaction to the virus itself, we were told that's essentially what a viral rash is.