Oh no, that must have been scary, did they say to be careful with anything else? I think banana and latex are similar to avocado? Did they give you a prescription for piriton?
We ended up in an ambulance to hospital after DD reacted really badly to cashew so we were told to avoid all new nuts, she was previously fine with peanut and almond so we carry on with those. She had a positive skin prick test for cashew and cows milk at 15 months, with the advice to avoid nuts until the next SPT in a years time ( when she'll be over 2), but to try the milk ladder in 6m.
There were loads of things that DD got hives from at the start of weaning that don't affect her now, avocado, salmon, sunflower oil, egg, as well as the usual high histamine foods like tomato. But I tried them again to be sure and over time she stopped getting hives. And like I said before I absolutely can't believe she can now eat a cheese sandwich without all of her usual instant (IgE ?) severe CMPA symptoms.
If they didn't give you a bottle of liquid piriton I'd definitely keep one in the cupboard, I know it says over ones but we got a prescription at 8 months, and it was a comfort to know it's in the cupboard. Try not to be nervous of the allergen foods, I think the recommendation is to give them one at a time with 3 days between?
Good luck, I know it feels daunting to start with.