the enzymedica 'lacto' enzyme blend is mild and could also be tried
if you or your child do not tolerate these, then you have severe biofilm and leaky gut with high histamine
candex may be the simplest test, but be cautious, the biofilm toxins released by the enzymes attacking the biofilm can be very nasty, just try tiny amounts (1/8th of a capsule?) and work up.
i had a biofilm from eating too much stewed apple over quite a while and three candex caused the most unusual pain and feeling in the intestine about 10 hours later, i couldn't do anything except walk around (may 2008) - an obstructed appendix from biofilm and sleeping on my back - see appendix problems on the osteoarthritis and joints page
activated charcol may help absorbing the toxins
thats really first base, you have to get there and if you are not, anything else in the way of therapies is a waste of time