Lupus is an autoimmune disorder that can show itself from a simple skin rash to a possible fatal systemic disease. Just because your dog has a rash doesn’t mean that it has lupus! If your dog has a rash, please consult your vet for testing. Rashes can also be more benign things such as food allergies, ringworm, or mites. For more information on lupus, please consult the links below.
Discoid Lupus picture
Discoid Lupus explanation
Very good article on the different types of lupus