Is this allergic reaction?

Hi Everyone,

My 15mth DD has food intolerance but for the first time she has a
reaction and i am wondering if it is an allergic reaction. We gave her
oat cereal with fruit on thursday, friday and she seemed fine. We
again gave her on saturday when she refused it and ate may be all of 4
or 5 mouthfulls around 8PM. When i took her for her diaper change i
noticed red bumps over her body and a few on her face. The next day
her cheeks seemed more redder and the spots on her body were still
there, if anything she had more of these on her body, hands and legs
as well. Her face still has the red bumps on her face and the bumps on
her body are still there but not so red. Could this be a reaction to
the oat cereal? I havent given her any oat cereal since saturday,
could an allergic reaction last this long (today is tuesday, so 3
days) or could it be something else?

Lastly, she started at a daycare last week and apparently there is
roseola going around but from everything i read, you are suppose to
have 2-3 days of very high fever before you break out with the rash
and even then the rash only lasts 1-2 days. My DD never had high
fevers, so i am thinking its not roseola.
Thanks,
Nitu