Doctor's views on lactose intolerance

Erbie and I visited the doctor this morning to find out what formula I should try next. It turns out his son was lactose intolerant too, so he knew all about it. He perscribed a tin of Cow & Gate Pepti Junior, in which the lactose molecules have been chopped up and so are easier to digest. However when I described the rash that came and went instantaniously he mused that it could be an allergy in which case I would need to take him for a scratch test at the hospital.
'Perhaps you could take him to A&E and then try feeding him', he suggested.
'Isn't that a little extreme?' I replied.