Hi potterone,
The symptoms will be a reddening of the nose membranes,rubbing the nose,sniffing,eventually the division between the nostrils will rot away, tell them to get help, don't know about it getting scabby, I can only comment on the couple of people I have seen taking it, good luck, Ray
before you say anything,watch the behaviour pattern,if it changes suddenly they might well be taking something,but it could also be a bad summer cold,so don't go accusing or assuming till you are 100% sure.