Infant/Toddler Allergies

My 1 yr old daughter was recently on a walk with her nanny and came home with bright red dots (elevated) on her face and red spots (non-elevated) on her legs and torso. (no white heads on the spots) They do not appear to bother her. Once inside the spots proceeded to clear up. This reaction has never happened before while on her walks. Additionally, her nose has started to run. Now, the  spots and dots come everytime she is outside. At first I thought, heat rash but the dots appear even when she is in the sun but not hot (i.e. in the car with ac). One pediatrician suggest sun sensitivity, but this is not the first time she has been out in the sun. I am stumped.
I am extremely allergic to ragweed; could she be developing this allergy also? Perhaps on a more sensitive level, i.e. any exposure or contact breaks her out?
I am really at a loss.

Thanks.

[laura1977]

my youngest daughter (2) when she goes out in the sun she gets what looks like at the time a bad sunburn even with sunblock on.  It does go away when she goes inside though.  Another option you might have is did she have sunblock on and had a reaction to that.  Has she had any of immunization shots lately?  My 5 year old got like a thousand red spots all over her after getting MMR.  But I just realized you said this has happened more then once.
Parents who have allergys (allergies) have children that are more pron to allergys (allergies).