Aversion to Sniffing

This is called misophonia. I have it myself - my aversions are to the sounds of people eating (sniffing doesn't bother me). There is a Facebook support group for it as well as many articles. There is therapy that can be done, but it's hard to find therapists who are trained to deal with it. For me, I make sure I have music playing when I eat with my family. But the KitKat commercials with the sounds of crunching incorporated in the song drive me through the roof! I have to change the channel. It's a hard thing to live with because no one understands - when I was a kid, my dad would get so mad at me and tell me to ignore it. As with any condition, it doesn't work that way. Look up Misophonia and see what you learn.

ETA: Glad to hear it! I was told I was crazy by my own parents. I don't know if it only recently became a classification with a name, but I lived my whole life not knowing it was a "thing" until a few years ago.

It sounds like a phobia. I'd get her some help if I were you. This is not normal and if she cannot find a way to deal with it on her own, then she needs a professional to help her. I also think that if you don't get her help, it will affect her relationships with everyone around her.

I must be weird too because I can't stand it either. All I can think of is 'they are sucking all that snot down their throat.... yukkkkkkkkk'
Any time I hear it I just want to hand the person a tissue and tell them to blow their nose.

Sorry if that's a gross answer.

I also deal with the same aversion. The sounds of people bouncing their leg, tapping, sniffling, clearing their throat repeatedly, chewing, and swallowing are like nails on a chalkboard for me. I usually try to find something else to listen to instead, or I rub my toes on the insides of my boots to divert my focus. Sometimes it works, and sometimes I end up with fingernail marks inside my palms from clenching my fists with frustration.

Perhaps give her something to fidget with in order to divert her focus too?