Has she had sesame seeds before? I understand that can be a pretty severe allergy but is not in the Top 8. My daughter has 4 of the Top 8 (eggs, peanut, fish and milk) plus cats and dogs so far and she just turned 2 in July. I would suggest children's benadryl. Although the label says under 6 "ask a doctor", she has been using it for severe (but not anaphylactic -- we have epipen jr for that) since she was 12 mos old. Doc said 1/2 teaspoon as directed and necessary (which is every 4-6 hours as needed but no more than 6 doses in 24 hours). Usually it only takes a dose or 2 for us. I would try that until you can get her to the pediatrician. Take a picture if you can BEFORE the benadryl so you have something to show the doc in case the hives go away. Take the bag with you (we did that with my daughter's first Top 8 allergic reaction at 12 mos) and ask for an allergist consult. We go to Dr. Hirani (she does mostly peds) and has an office on the NW side of Chicago off of Talcott an also another office in Des Plaines off Golf Road before you get to Golf Mill. ###-###-#### is the allergist number -- Waheeda Hirani. If you do the blood test, they give you an order and you get it drawn at the hospital. Good luck and keep us posted! I hope it is a fluke -- but safe than sorry!
Wow- I just noticed you said benadryl isn't helping...if the rash gets worse I might suggest you take your kiddo to the ER if the itching is unbearable. Might need something stronger like Epi to stop the itching and rash.
Unlike another poster-- my daughter's food allergy hives are not large but are more eczema-looking and spread on face, around mouth, torso, or crooks of arms/knees depending on what she ate...some show up right away but those from milk take a day or two to show. Every kiddo is different.
I kind of doubt it is a common childhood virus if there is no fever -- my daughter had roseola and hand foot mouth -- high fever with both...but some kids just don't spike fevers so who knows!