Lets hope its not, but worse case senerio is the hereditary disease known as HERDA. I have never dealt with it, but have known of a few horses with it.
Being an auction horse and possibly a QH, might be to rare for your vet or friends to know about.
horsecity.com/stories/031204/hea_herda_KT.shtml
bringinglighttohypp.org/HERDA.html
thehorse.com/images/content/hc_herda/hc_herda2.html