Dd who is 6 had flu last week. Picking up and pretty much back to normal but now coming out in hives. Given her piriton but not really controlling it completely. She had this once before and GP was unconcerned even though she was quite puffy too following on from a virus. On our way to Devon and she is now fast asleep. Will continue giving piriton every 4 hours. Are they ever dangerous? Should I be seeking medical advice?