Rats tail discolored and bumpy

Question
Hello.  I was searching the internet and could not find
any articles regarding my rat's condition.

I have 2 female rats both 9 months old.  A few weeks ago, I noticed one of their tails was getting darker and patchy in color (black, grey and white patches).  This discoloration starts about 2 inches from her rump to the tail's end.  A few days later, I felt the tail and it was lumpy and bumpy where the discoloration
is.  I didn't think too much of it.  She didn't seem in pain when I touched her tail nor was her tail dragging or drooping on the ground.  She would still wrap her tail around my finger.  A few days ago, I noticed that parts of her tail looked a little scabby and it appeared that some scabs had peeled off in some places, showing white underneath.  I am not sure about the peeling though.  She
still seems very happy and eats and sleeps well, but I am concerned, especially since I couldn't find any good information about this condition on the internet.  By the way, I got them from a good breeder, they are fed Harlan Teklad blocks, fresh fruits/vegs, and live in Aspen that is changed weekly.  So I think I'm doing the right things.

Since my rat seems otherwise happy and healthy, I have not yet gone to visit to a vet.  I had a negative experience with our local vet as the first time I took my other rat, they
gave her meds and scared me to death about her condition when it just turned out to be diarrhea and she was all better the next day, after a couple of hundred dollars left my pocket.  

Do you have any knowledge about this condition?  Should I be worried? Thank you for your advise.


Answer
The rat may be dehydrated which can cause dandruff and usually will cause the tail to start loosing skin and appear blotchy.  Your best bet is to make sure she is drinking lots of water, hydrate the air using a humidifier, and keeping it clean. Here is a great site that will help you and even gives pictures for you to view. Also, just a fun fact, rats tails regulate their body temp and they sweat from the feet :)

http://www.ratfanclub.org/skin.html