How long before dairy/soya causes a reaction?

[PracticalCat]

DS1 (2) has just outgrown his dairy allergy. He also had a sensitivity to soya.

DS2 (9 weeks) is breastfed and might have some dairy issues. I've cut dairy from my diet for the last week and a half and it seemed to be helping. But since yesterday the original symptoms have returned.

I don't think that I accidentally ate any dairy, but had a soya latte on Saturday. Could the soya be the cause of the regression or would it have had an effect sooner?

I had GF sausages which contained soya last Tuesday. By Wednesday night, DD2 was screaming and refusing to settle (from 1:30 - 5:30am ) and the screaming continued for 5 days. She got a facial rash on Friday which is still there a week later. However, I do have to stress that all this was after recovering from a sickness bug and during teething for her second tooth, so symptoms were probably exacerbated.

Soya is a very strong allergen, you should definitely stop using it, and be aware that most of the sweets and chocolate also contains soya lecithin