Raw spots on dogs nose

Question
I have a year old terrier/mix with two raw red spots directly below her nostrils.  The spots are about the size of a lentil.  They vary from time to time-sometimes appearing to be raw and other times seem to dry up.  They look a little like cold sores, but there is no white blister-just a circular raw, red spot.  The dog was recently chewing on a redwood deck rail, so I wondered if it could be an allergic reaction to that or to some pollen in the air.  Every plant is in bloom around here, so I wondered if she might be breathing in some allergen and the nose spots are the result.  The dog has no concern with them, doesn't mind if they are touched, and doesn't seem to be ill in any other way.

Thanks-

Stephen Kellam

Answer
This could certainly be trauma in which case a steroid ointment should help. It takes several weeks for these to heal because they lick at the area so often.

It could also be an autoimmune condition like pemphigus or discoid lupus.  Check with your vet about these if the lestions are not healing.