Many, many, many years ago when I had my very first job, I encountered a stray dog that was hanging around the industrial area where I worked. It looked like she had just had puppies since she had the tell tale signs of flat mammary glands. A few of my co-workers and I noticed that she was very smart. Someone had reported a stray dog in the area and animal control was trying to find her. We noticed that when the animal control truck came around we could see her hiding behind cars or ducking out of sight from them.
It was my sister and I that ended up feeding the dog from a distance since the stray was not that trusting of people. It took about a week until we got close enough to see her true condition. She was thin but it was the lack of hair that startled us the most. She was a black dog and from a distance it looked like she had brown spots. When we got closer we saw that those brown spots was bare skin.
We ended up taking her home. The best hair loss treatment for her was a few baths and lots of good food. In a few months that thin, balding stray dog turned into a black, shinny. well muscled Labrador Retriever. She ended up becoming my dad's dog and lived another 10 years with him before dying of old age.