A dog’s immune system is its defense system, made up of antibodies, white blood cells, and other substances. This defense system works to reject foreign bodies and attack infections. It differentiates between “self” cells and “non-self” cells by markers – called antigens – located on the surface of every cell in the dog’s body. Problems arise when the dog develops an inappropriate immune response against its own cells, or against transplanted organs, blood, or skin grafts. When the immune system attacks and rejects its own cells, it is called an autoimmune disorder. Autoimmune diseases can target the nervous system, blood, blood vessels, skin, gastrointestinal system, endocrine system, or multiple organs or musculoskeletal systems. Some of the most common forms of canine autoimmune diseases are thyroiditis, allergies and autoimmune diseases of the skin, autoimmune hemolytic anemia, lupus (systemic lupus erythmatosus and discoid lupus), generalized demodectic mange, pemphigus, rheumatoid arthritis, and polyarthritis. Less common forms include immune-mediated thrombocytopenia, canine inflammatory bowel disease, and myasthenia gravis. Thyroiditis is the most commonly-reported canine autoimmune system disorder.
No one knows exactly what causes a dog’s immune system to suddenly start attacking its own cells. There are several possible triggers, such as: environmental factors; genetic or hereditary factors; toxic metal exposure; an injury; overuse of vaccines, antibiotics, or steroids; bacterial or viral infections; food preservatives; nutritional deficiency; exposure to the chemicals in chemical pest treatments and pesticides; sun exposure; or extreme periods of stress. Autoimmune diseases are not contagious.
No one can be 100 percent certain if a dog is predisposed to an autoimmune disorder. Generally, no dogs with chronic autoimmune symptoms should ever be bred. This will help to prevent it from passing its genetic predisposition to its litter. Crosses of dogs that tend to produce autoimmune disease should not be bred. Siblings, parents, and offspring of a dog diagnosed with an autoimmune disorder should never be bred with an affected dog. These dogs (as long as they show no signs of autoimmunity) should be mated with dogs that come from families where no autoimmunity is present. Dogs whose siblings or parents have autoimmune problems but show no sign of it themselves should be monitored until they are three to four years old before breeding, to make sure they don’t develop the disease.
Proper immune support is essential in all dogs, but even more so in dogs at risk of developing any of these disorders. Holistic vets believe a natural, species-appropriate diet free from preservatives and other chemicals, and supplements that support the immune system will work to keep dogs healthy. Essential fatty acids supplementation helps keep the skin and gut strong and healthy. Since the skin and gut are the immune system’s two first lines of defense, EFAs can help support the immune system. Other supplements that can help are probiotics and digestive enzymes. These help with digestion, but more importantly, help keep the digestive system strong which aids in proper immune system function. The elimination of stress, toxic pollutants, and other environmental triggers can help reduce the occurrence of these disorders.
Good record keeping, diligence, knowledge, and foresight will reduce the risk of litters developing these devastating and potentially fatal disorders.
There are many possible general symptoms of autoimmune disease. They include body odour; anemia; diarrhea (with or without blood); weakness; intolerance to exercise; nasal, oral, and anal lesions; lethargy; depression; reproductive difficulties; weight gain or loss (if thyroid is affected); seizures; stiff joints; dull or scruffy coat; lameness; skin lesions; itchiness; skin ulcerations; discolouration of the stool or urine; behavioural changes; cold intolerance; thickened skin; poor wound healing; unexplained soreness; altered pigmentation; excessive licking of the paws; inflamed ears; pale mucous membranes; unexplained swelling; dry eyes; blisters or pus-filled sores; droopy eyelids; problems swallowing; and loss of appetite. A dog may exhibit any combination of these symptoms. Take your dog to the vet if you notice any of these signs.
Dogs at Risk
Breeds commonly affected by hypothyroidism are Miniature Schnauzers, Poodles, Dachshunds, Boxers, Golden Retrievers, Cocker spaniels, and Labs. Both males and females are equally at risk to develop hypothyroidism.
Breeds most often affected by pemphigus are German Shepherds, Shetland Sheepdogs, Akitas, Bearded Collies, Chow Chows, Collies, Dachshunds, Doberman Pinschers, Newfoundland Dogs, and Finnish Spitzes. Males and females are affected equally.
Dogs most prone to lupus are Siberian Husky, German Shepherd, Brittany Spaniel, Collie, Shetland Sheepdog, and German Shorthaired Pointer.
Breeds most prone to autoimmune hemolytic anemia (AIHA) – where the body attacks the red blood cells – are Lhasa Apsos, Cocker Spaniels, Old English Sheep Dogs, Shih Tzus, and Poodles. Middle-aged females are more at risk to develop AIHA. Some drugs like analgesics, cardiovascular drugs, vaccines, and antibiotics, as well as certain viruses are suspected to trigger AIHA.
Testing and Diagnosis
When a dog is suspected of having an autoimmune disorder, blood, urine, and stool samples may be sent for testing. Some diseases such as hypothyroidism can be tested for in much the same way as for humans. Other diseases, like generalized demodectic mange, are diagnosed based on case history and appearance of the lesions. Myasthenia gravis has no diagnostic tests.
Treatment and Remedies
A dog’s prognosis depends on the type of autoimmune disorder with which it is diagnosed. Some impact the dog’s quality of life but are not severe, if managed, and some are fatal, even with treatment.
Holistic treatments for autoimmune diseases include plant sterols and sterolins, selenium, vitamins A, C, and E, and antioxidants such as coenzyme Q10, systemic enzymes, carotenoids, green tea, and alpha-lipoic acid.
Standard veterinarian treatment of autoimmune disorders is via immune-suppressing drugs such as cytoxin, cyclosporine, azathioprine, danazol, and steroids (dexamethasone and prednisone). Steroids work to stop the immune system from over-reacting, but have harsh side effects and must be closely monitored. Over-use of steroids can actually contribute to autoimmune disease. The dog must be fed a diet and supplements that help to support the immune system as part of this treatment.
Dogs with autoimmune hemolytic anemia may require blood transfusions, but this can sometimes make the disease worse due to the foreign blood. This is usually only done in life-threatening situations, and with great caution and attention. Some vets choose to use an artificial blood product called Oxyglobin. Some dogs with AIHA respond well to the surgical removal of the spleen. This causes the dog to produce fewer antibodies against the red blood cells. The spleen is the organ primarily responsible for killing red blood cells.
Hypothyroidism may be treated with thyroid hormone supplements such as L-thyroxine. There are holistic and homeopathic treatments available as well.