bearded dragon skin condition?

Question
We have had a happy and healthy bearded dragon for about a month now.  He has adjusted well to his new 4x2x2 enclosure, and has some favorite basking sites and shelter under logs, (sandy bottom).  He's eating well - crickets and veg both.  We have noticed a greyish patch -- actually a one-cm band at the base of his tail, on his topside.  It seems to be growing slowly toward the tip end of his tail -- it seems the band is getting bigger!  The scales do look somewhat puffed there, and the colour is definitely greyish.  He is an orange-brown, and so the colour change is quite noticeable.  Is this a skin condition?  We have read of a fungal dermatitis that BDs might get, and are unsure.. I suppose a vet visit is in order?

Answer
Hi Kristina, I like to eliminate the most simple and obvious possibilities first. Has he already gone through a shed cycle in the month that you have had him? Skin of any colour will appear grayish and raised as it separates from the new skin beneath in preparation for shedding. These areas will also appear to "spread" and he will take on an overall faded appearance before the old skin starts to break away.
Unless your dragon was previously treated for coccidia, it is unlikely that this is the dreaded yellow fungus. The sulfa treatments for coccidia predispose a dragon to this particular condition, there is a very consistent link in the clinical cases studied.

I have included a link, for your comparison, to some photos posted by reptile vet Marc Kramer. These cases appear to be pigment abberations, without the skin being raised or puffed.

http://homepage.mac.com/exoticdvm/reptile/PhotoAlbum84.html