FPIES - how did you know it was this?

[YukoandHiro]

Wondering if DD2 (almost 7 months) had an FPIES attack today. DD1 has multiple IGE allergies but I've no experience with FPIES. I thought it was her first gastro bug but she's rallied already - seems really odd. It was profuse vomiting for an hour, and lethargy and she looked poorly. She slept for an hour and then after that has held down feeds and seems normal. She has no known allergies but she's not had any major allergens introduced yet apart from wheat and coconut as we're wearing slowly. She had avocado for lunch.
I was planning to try dairy next week but I'm scared now.

Hi just wondered what the outcome to this was ? I’ve given my son avocado twice and both times he has projectile vomited severely. He is non ige allergic to dairy. I’m so anxious about weaning as we’ve just started and the vomiting was so bad