Advice please. DD2 seems to have suddenly developed an allergy & we are about to fly off on hols.

[Avocadoes]

DD2 is 18 months and has no history of allergies. Yesterday I gave her a pasta sauce with onions, celery, carrots, tomatoes and cheese. After a few bites she started grabbing her throat and whining. Then hives and red blotches appeared all I've her kneck and lower face. I gave her piriton and 20 mins later the rash faded. Then this lunchtime she had pizzawith a cheese, tomatoes and chorizo topping. The same thing happened. Again piriton fixed it?

Can allergies suddenly appear like this? Dies she need to see a doctor? We are flying to the US tomorrow. Should I avoid giving her wheat, tomatoes or cheese (the common ingrediants between the 2 meals) until we return?

TIA.

Sorry. My attempt to type on my phone has rendered that message almost unreadable.

I would phone NHS direct and ask their advice.

Lots of very young ones are sensitive to tomatoes .
If it was me i would take some piriton and go away and see doc when you get back.
Has she reacted to wheat /cheese/tomatoes on their own before?

It could well be the celery, when someone is allergic to it it often produces a very strong reaction like this. It is often an added ingredient in tomato sauces too.
Carry antihistamines with you wherever you go. You can take a small, single dose with you on the plane. We went to the US at Easter and were able to carry this along with inhalers and Epipens without a problem.