Am I Allergic To "Puggles"?

A certain mix?? I don't know... however my sister-in-law thinks she is mildly allergic to Caney, my 2 yr old boxer, after being around her several times, however she has never shown any sensitivity to Creek, my 8 yr old boxer. She also has no problems with her weimaraner. It's just the ONE dog she's allergic to. Go figure!