Having been treated at hospital and given steroids, she was sent home with advice to restrict her diet.
Tests showed allergy to foods, pollens and mould...
Eventually tests at Guy's Hospital revealed allergies to pollen, peanuts, sesame and most significantly a particular mould called cladosporium herbarum commonly found on window frames, fridges and buildings that are poorly ventilated. This made sense since the school buildings were old and poorly ventilated and one class, where she had most of her attacks was in a temporary building with black mould on the windows.
Please read the article Could you be allergic to your house?