Amber
I have done quite a bit of research then. There's no known cause for Roseola, it's basically a form of viral illness, most commonly affecting those between 6 mths and 2yrs. In fact KK didn't diagnose my girl with Roseola (I "diagnosed" her with that given all the tell tale signs). KK merely dismissed her as having viral fever after her blood and urine test turned out ok (cos back then was early stage of Roseola with some angry rashes).
Anyway, I suspect it got to do with the MMR injection since someone in this thread vaguely mentioned that MMR is basically the injection of 3 viruses to get our todd's body at the same time.
Bingo, just surfed the web briefly, it's indeed one of the possible side effects of MMR. I hope I won't put off some mummy who's about to go for MMR. By exposing our todd to 3 viruses at the same time may be too much for some, hence the side effects. There were also discussion whether we should even space out the injection (then again, it means yr todd will need additional injection and may affect a small %).
Since your girl still having high fever, you need to continue to sponge her to bring her temp down (no joke have burning hot fever above 39.5). Best to see your GP/PD if her fever did subsidize, then she may need to go for blood test and urine test to rule out other possibility.
Once the rashes start to appear, I merely applied some calamine lotion spread thinly over my girl's body - since she's too traumatised to see another doctor after her trips to 24hrs clinic and KK A&E (diagnose, blood test, urine test,etc).
Sorry for the long post, that's why I tend to "lurk" and not post.
MMR Side effects
http://hcd2.bupa.co.uk/fact_sheets/html/mmr.html
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"The three viruses in the vaccine act at different times and may produce side-effects as they start to work.
The measles part starts to work six to 10 days after immunisation. Your child may have a fever, develop a measles-like rash and go off their food.
About one in every 1,000 immunised children may have a fit caused by the fever. This is called a febrile convulsion. However, the rate of febrile convulsions caused by measles is much higher - one in every 200 children who gets the disease.
It's rare, but your child may get mild, mumps-like symptoms (fever and swollen glands) about three weeks after immunisation as the mumps part starts to work.
Children may get a rash of small bruise-like spots in the first six weeks after the vaccination, but this is also very rare. This can be caused by the measles or rubella parts of the vaccine. Take your child to your GP to be checked if you see spots like this.
Fewer than one child in a million develops encephalitis (inflammation of the brain) after the MMR vaccine. However, if a child who hasn't been vaccinated catches measles, the chance is higher - between one in 200 and one in 5,000.
Side-effects of the vaccine are usually mild and, most importantly, they are milder than the potentially serious consequences of having measles, mumps or rubella".