Autoimmune Skin Problems
Another set of skin problems in dogs comes under the heading of autoimmune problems. In these cases, the dog's immune system reacts against his own skin cells. There are a number of skin-related autoimmune diseases in dogs. Some of these diseases just affect the skin, while others are generalized immune problems, with skin troubles just one of the possible symptoms. All of them require close cooperation between you and your veterinarian to keep your dog in the best possible condition. Topical or oral corticosteroids or other immunosuppressive drugs may be needed along with occasional antibiotics or special baths and diets.
The Pemphigus Complex
Pemphigus is a skin disorder that has a variety of forms. Pemphigus foliaceous is the most common form. Dogs with this disorder often develop scabs and pustules on the head and feet that gradually spread over more areas of the body. Blisters are also present, but they rupture easily and aren't seen very often. With the open skin sores, dogs often develop secondary bacterial infections. Breeds such as akitas, chows, bearded collies, and Doberman pinschers are prone to this.
Pemphigus vulgaris is the most severe form of pemphigus. Dogs with this condition develop severe ulceration at areas where hairy skin joins mucous membranes, such as near the mouth, nose, and anus. It may also affect the feet and can even cause nails to fall out. It is common for other serious immune problems to occur as side effects of pemphigus vulgaris. A skin biopsy may be required to get a clear-cut diagnosis of this disorder. Dogs with pemphigus of any type will almost always require prednisone therapy along with other immunosuppressive drugs such as azathioprine or even chemotherapy drugs.
Chemotherapy drugs often work as immunosuppressives to slow down or shut off the reaction of the body against its own tissues. For this reason, these drugs may be used to help dogs with autoimmune problems. Cyclosporine is an example of one of these medications. Unfortunately many such drugs have side effects, so careful and consistent monitoring of your dog's health is important.
Systemic Lupus Erythematosus
Systemic lupus erythematosus, or SLE, is an immune disorder that affects a wide range of body systems, from neurologic to skin to blood components. In a dog with SLE, the immune system has two defective actions. Immune complexes (clumps of cells formed when antigens and antibodies interact) can be deposited in organs and interfere with their function (as described for glomerulonephritis, on page 153). This disease also stimulates the formation of autoantibodies — antibodies that react against the body's own normal tissues. Dogs with SLE will show skin reactions, ulcers on oral tissues, possibly behavior changes, and even additional autoimmune problems with blood cells and platelets. (Refer to the description of AIHA and autoimmune thrombocytopenia on pages 158 and 159.)
How can I figure out what all those complicated disease names mean?
Sometimes there are clues to what a disease name means. For instance, the suffix “itis” means inflammation. So arthritis is an inflammation of the joints, arthro being the Greek word for joint. The suffix “osis” or “osus” simply means that the condition is abnormal.
Dogs with SLE are diagnosed by a combination of biopsies of affected areas and blood tests. Treatment for SLE usually starts off with corticosteroids, but immunosuppressive drugs may also be required. Immunosuppressive drugs act to limit the body's response to infection and inflammation. This group of drugs includes some medications such as aziathioprine and cyclopsorine.