I got Brooke when she was 5 months old and 2 weeks after I got her she came down with ringworm! She gave it to me and my 2 chihuahuas! As the other posters have said, it took like 2 -3 months to get rid of and there were many baths, stinky sulfur dips and medicines plus many trips to the dermatologist. It is contagious so you have to keep the dog at home during this whole time. If you get this pup at 10 weeks, he may not be through with the treatment and then you will not be able to socialize him correctly because he still will be contagious. I had to wait until Brooke and the other's had no more spots and then 2 weeks after that we were allowed to go outside. Just keep this in mind if you still decide to go ahead and get him. Whatever you decide, I wish you well.
