Allergic to cheap ketchup

[Mybabymia]

Hi. My 2.5 year old daughter loves tomato ketchup. She is fine with Heinz but whenever she has the cheap sachets that you get in cafes etc, she gets the red blotches around her mouth where the ketchup has touched her.
My question is, if anyone knows what is in the cheapo brands that isn't in heinz that is causing this? Would like to try and avoid it in future if possible.
Thanks.

its a bit acidic , and cheaper brands have more vinigar , so the sensitive skin of a young child could get blotchy skin.

nothing else with any other foods? ezcema?etc?