David and Serena; et.al.
 
You will probably get more "expert": information, but the kits you saw may
have had it caused from switching too quickly to hard food.  As far as I
know, what you saw fits the use of the term.  My Sachi got it from being
"dirty" after going potty.  I used a wet wipe made for toilet use to gently
clean her bottom.  and put a dab of colloidal silver gel made with aloe on
with a Q tip.  She squeeked a bit, so I knew it was tender.  The next
morning, it was perfectly normal!!!:) The gel I used is from Silver Wings
company, I don't have any connection but it really worked.  There are other
medical causes like botched de-scenting surgery, etc.  that others will
probably tell about, so I'll stick to what I had experience with,.
 
Hope that helps, enjoy.
 
    Gary & the gang of fur
 
    The pure of heart carry within a source of good.
[Posted in FML issue 1580]