Milk ladder failure after apparent partial success?

[FoofFighter]

DD is nearly 3.

She was diagnosed CMPA at 4 weeks old.

First did milk ladder at around 1yo and she failed after one day. The second attempt was more successful - had waited a few months and tried again and managed to get around half way up the 12 step one, so basically she's been tolerating normal amounts of cakes/muffins pancakes, biscuits, meals cooked with milk in them but I never managed to get her any further on and she's been happy enough for the past 18m at this level.
DD hasn't been quite right for a while, a week last Tuesday it started - she was sick 1x about 3 days apart each, sleepy, sore tummy, nothing wrong with bowel movements though. No other obvious signs of illness/virus.

She's today done a very strange poo, half normal, half yellow slime and it absolutely stank, like when a dog gets that Parvo virus type thing, that acrid back of your throat just know it's got a bug in it kind of smell.
And now she's complaining of a sore tummy again and was writhing around a bit in discomfort. Have given her a warm hot water bottle and she said it helped, and has now at 4.50pm asked to go to bed. And shes sleeping now.

She's been a little off her food but not much tbh, nothing new has been given apart from Robinsons barley water, no accidental exposures.

Any ideas anyone?

Wondering if I need to think about going totally dairy free with her again.

Can they reach a tolerance level where when they hit it then the body just rejects it?

[fraggle84]

Dd had a delayed reaction at 1 years old, worked her way up the ladder then a month later showed all the signs of her cmpi. Her consultant said its not uncommon and to go back to dairy & soya free

I'd ring her consultant and ask