Immune-mediated is a term used to describe a situation in which the immune system attacks the body, causing a disease, infection or illness. These diseases may also be referred to as "autoimmune" diseases. It is unknown why these types of conditions occur in dogs. Some veterinarians believe it may be genetic, while others say it may be environmental.
Also known as hyperadrenocorticism, Addison’s disease occurs when the adrenal gland is no longer producing an adequate amount of certain hormones. These various hormones control the body’s metabolism and are also help balance electrolytes, sugar, fat, protein and potassium. Symptoms of Addison’s disease include anorexia, vomiting and weakness as well as lethargy and a general lack of interest. Fortunately, Addison’s disease can easily be treated through replacing the hormones normally produced by the adrenal gland.
Ehrlichiosis occurs when a dog comes in contact with an organism known as ehrlichia. Ehrlichia causes issues with the blood in the dog, causing the immune system to attack its own blood. By doing so, the blood loses many of the necessary clotting factors, which can be life-threatening. Symptoms of ehrlichiosis include fever, loss of appetite, anemia, depression and lethargy as well as shortness of breath, pain in the joints and stiffness in the muscles. Treatment for ehrlichiosis involves antibiotics, which are administered for up to four weeks. If serious damage was caused by the immune system, additional medication will be administered to control the issues.
Also known as anal furunculosis, perianal fistulas are small lesions that occur around the anus of the dog. These lesions are extremely painful and can drain fluids as they progress. Perianal fistulas usually occur in dogs who are prone to developing other immune-mediated diseases; however, the true cause is still unknown. Additional symptoms of perianal fistulas include a foul discharge, lesions that may start in the anus and spread through the body, lack of bowel movements or blood in the bowel movements. Dogs may also exhibit a change in behavior and in severe cases, pain can prevent movement of the dog’s rear quarters. Treatment involves clipping the affected area and cleaning it thoroughly with an antiseptic. In severe cases, dogs may need an oral medication containing cyclosporine and ketoconazole ,which will need to be taken for up to nine weeks.
The cause for immune-mediated polyarthritis is unknown, but the disease occurs when the immune system begins to attack the joints of the dog. Inflammation occurs and you may notice your dog has an altered gait. He may also be reluctant to move, as well as show lameness in the affected limbs. There may also be a fever present. For most dogs, treatment involves immunosuppressive drugs, which reduce the efficiency of the immune system.
Common in smaller breeds of dogs, rheumatoid arthritis usually occurs between the ages of 5 and 6. When rheumatoid arthritis occurs, the immune system malfunctions and begins to attack some of its own proteins. Inflammation occurs and can affect many of the joints in the dog. Symptoms include swelling, pain, lameness of the affected limbs and in severe cases, muscle loss can occur. Treatment can vary from veterinarian to veterinarian, but some common methods include anti-inflammatory medications, steroids, immunosuppressive drugs and pain medication.