Hi there. It appears that the kid with the rash
has urticaria; the others appear to have food poisoning
. Since you are out in the ? wild, perhaps they ingested something in the last 24 hrs that caused the problem? berries/mushrooms? An antihistamine tablet should help the former & you may require antibiotics for the latter with lots of hydration & fluids, water etc. cheer & take care. The sooner you get them back to base camp, the better. Cheers!