"Rat tail" on Allie, questions

 One flea can cause an allergic dog to chew off it's tail, but a bare rat tail (or tail with a few scraggly hairs) can be a symptom of adrenal issues.

 Cushing's and Addison's are the two big ones. It's something you need to have your vet check for, if it's a possibility.

Cushings is *sometimes* but usually not idiopathic (no discernable reason) -- typically it comes after years of steroids.  It's NOT a diagnosis you want. 

Is the skin dark or discolored or shiny?  At ALL abnormal or is there just no hair?

However -- a lot of things can cause that -- from a liver imbalance to fungal issues. 

Particularly if the skin is dark or shiny, try this -- get some pure tea tree oil (you can even get that at Wal-mart -- and I mean the essential oil NOT hair stuff with tea tree in it -- it's on the aisle where the herbs are -- usually a little 2 oz bottle is less than $5).

Just once a day massage a drop of tea tree into the bare areas -- try it for a few weeks and see if it changes it. 

 Yes, Cushing's is not a diganosis you want. But if you do suspect, I would have the testing done. If it is not, even better, but if it is, it is not a good idea to let it go on without treatment.

http://dawgbusiness.blogspot.com/2010/02/hypo-versus-hyper-continued_17.html