discoloration and foul odor

Question
my 10 year old toy poodle has started to have a very foul odor that does not diminish even after bathing. the smell seems to be coming from the rear, which is also the same area where the discoloration is very prevalent. I think that the smell is medicinal. Due to the economy I cant afford to take him to the vet any longer. Please help

Answer
Hello Cynthia,
Your dog most likely needs his anal glands expressed.  The anal glands are located on either side of the dogs anus and produce a smelly liquid that they express when they have a bowel movement.  Sometimes, the anal glands get blocked or impacted and need to be expressed or they can cause irritation or pain.  You might see your dog scooting his rear on the floor to help him express the glands on his own.  
Your Groomer can express them when you take your dog in for a grooming, or you can express them yourself at home.  If you choose to do this at home, you will need to get your dog into the tub as the fluid from the glands can spray out, and as I mentioned, it can be rather smelly.  
You will want to raise the dogs tail and feel on either side of the dogs butt hole.  If the glands are really full, you will see 2 bulges on either side of his anus.  Gently squeeze both bulges together towards the anus.  You will either see a brownish liquid or a thick paste-like substance ozze out of the glands.  This can be uncomfortable for your dog, so you may need help holding him still while in the tub.  
The other reason that your dog can get a smell like this could be from medication (as you indicated) or due to allergies or even enviromental hazards, such as lawn treatments or pollution.  
You can try washing your dog with a shampoo mix that is commonly used for skunk sprays.  
You use 2 Cups Hydrogen Peroxide, 2 tsp Baking Soda, 1/4 cup Dish Soap, and 4 cups water.  You may want to use less dish soap if its concentrated or you will have way too many soap suds (you may not be able to find your dog in all the bubbles, Kim smiles)  Don't keep this solution in a bottle with a closed top or it will burst the bottle.  Also, try to use up all the soap because it loses its potency as it ages.  Scrub your dog with the mixture, and let it sit on him for about 3 minutes.  Rinse and then you can shampoo with his regular shampoo and conditioner.  
This should help remove any smell that your dog has on his skin.  
As for the discoloration, that is debris that has come to the top of the skin and it will gradually fade as your dog sheds his skin.  

I hope this has helped you some.  If you have other questions for me, please feel free to ask.  
Thanks for using AllExperts.com,
Kim