Yes. Mange is contagious. Get those dogs to a veterinarian ASAP!
It depends on if it is demodectic or sarcoptic mange. "Red mange" has been used to describe both. Demodectic mange is a mite that all dogs have-- they receive it from their mother shortly after birth. Sometimes the populations of this mite grow out of control due to immune issues, large amounts of stress, or adolescence. Sarcoptic mange is contagious to both humans and other dogs, but is easier of the two to treat.
Demodectic mange is not contagious all dogs carry this mange. But the reason a dog will have an issue with the mange getting out of control is due to another underlying issue, such as yeast. Vets will treat the mange with ivermectin, prednisone and antibiotics when really all you need to do is change your dogs diet. Go to www.milehighbullmastiffs and there is a link to a book that will tell you how to cure this and how to keep your pet as healthy as possible for the rest of it's life.