my chihuahua

Question
I just got a 9 week old chihuahua puppy, and my other chihuahua seems to be very attached to her. I found out recently that my new puppy has congenital mange. But after I found out, my other dog always howls when I leave the house, and when he howls hes sitting right next to my other puppy. Why is he howling all of a sudden??

Answer
Sometimes dogs howl as a way of "calling" a departed pack member back to the group.  Your puppy is probably just too young to howl, even though the older dog now thinks of her as part of his social group.  I doubt it has anything to do with the mange situation.