Autoimmune Diseases
Canine autoimmune diseases cause the immune system to attack the body's own cells and tissue. An autoimmune disorder can be life-threatening to dogs depending on which organ or tissue is rejected. Autoimmune disease covers a broad variety of disorders in dogs that affect the immune system.. A dog’s immune system is a network of white blood cells, antibodies, and other defenses in the body that fight off infections and foreign substances, including bacteria and viruses.
Canine autoimmune diseases cause the immune system to attack the body’s own cells and tissue. An autoimmune disorder can be life-threatening. Treatment depends on the kind of autoimmune disorder. Here are some of the types of autoimmune diseases that affect dogs:
Systemic lupus erythematosus (SLE)
Systemic lupus erythematosus (SLE) is an autoimmune disease in which the body's immune system has become hyper-defensive, attacking the cells, organs, and tissues of its own body as if they are diseases that need to be destroyed
High levels of circulating antigen-antibody complexes (called a type III hypersensitivity ) are formed and deposited in the filtration portion of the kidney, the synovial membranes (the soft tissue that lines the space within joints such as the wrist, knee, etc.), and in the skin, blood vessels, and other sites in the body. Antibodies that are directed toward self-antigens that reside on and within cells, such as erythrocytes, leukocytes, and platelets (three kinds of blood cells with type II hypersensitivity), may also be produced. Finally, type IV hypersensitivity may also be involved when cell-mediated immunity is directed against a self-antigen.
SLE is believed to be underdiagnosed. Certain breeds are more likely to get it including Afghan Hounds, Beagles, Collies, German Shepherds, Irish Setters, Old English Sheepdogs, Poodles, and Shetland Sheepdogs. Symptoms usually appear around age six, but can show up at any age flaring up or going into remission for periods of time. SLE can affect the skin, heart, lungs, kidneys, joints, blood, and nervous system as antibodies in the blood attack the body’s own cells and tissue. Usually more than one organ will be affected. Symptoms depend on where the disease is localized. Symptoms to watch for include:
- Lameness or pain in one or more joints and muscles
- Increased drinking or urination
- Ulcers on the face or feet
- Lesions, scars, ulceration, or crusting on the skin
- Alopecia (hair loss)
- Loss of pigment in the nose
- Fever
- Anemia
- Thyroid problems
- Swollen lymph nodes
- Kidney infections
- Spleen, liver, or kidney enlargement
SLE was reported as a hereditary disorder in a colony of German shepherds. Usually the dog will show symptoms by 6 years of age and both sexes are equally involved.
Clinical symptoms depend on type of attack, along with the type of autoantibodies. Genetic, environmental, pharmacologic, and infectious factors may play a role in the appearance symptoms such as letahrgy, loss of appetite ( anorexia ), and fever , which is especially seen in the acute phase. Regional symptoms include:
Musculoskeletal
- Destruction of the soft tissue lining the surfaces within the joints
- Swollen and/or painful joints
- Shifting-leg lameness
- Muscle pain or wasting
Skin
- Skin sores
- Redness, scaling, ulcers, depigmentation, and/or hair loss
- Ulceration of the mouth, anus and nostrils (where regular skin stops and mucosa begins).
Renal/urologic
- Deposition of immune complexes in the kidney
- Hepatosplenomegaly - enlargement of the kidney and the liver
- Blood/lymph/immune system
- Antibodies attack erythrocytes, leukocytes, or platelets (red and white blood cells)
- Lymphadenopathy - swollen lymph nodes
- Other organ systems may be affected if there is deposition of immune complexes or antibodies, or when T cell-mediated cells (lymphocytes) attack
The causes of SLE are unknown, but there is a hereditary component for some dogs. Surprisingly, ultraviolet light makes the condition worse. With secondary AIHA, the surface of the red blood cells become altered by an underlying disease process or a toxin. The dog's immune system then recognizes the altered red blood cells as 'foreign' invaders. It can be triggered by cancer, infection, blood parasites, drug reactions, snake bites, chemicals, toxins, or bee stings. Neoplasia or cancer is the most common cause of secondary AIHA in dogs..
If the AIHA is secondary, the treatment is directed at the underlying cause. If no underlying cause is found, immunosuppressive therapy will be used and many dogs to treatment with doses of corticosteroids. Sometimes a combination of immunosuppressive medications to get the condition under control. Most veterinarians can handle simple cases, but with complex cases, your veterinarian may recommend a referral to an internal medicine specialist.
The outcome for dogs with AIHA depends on the diagnosis, aas well as the dog's health at the time of diagnosis. Often drugs can manage the condition. Once the dog's condition improves and the anemia resolves or stabilizes, usually they will taper off the immunosuppressive medications over a period of several months to lessen any side effects. Relapses are common with this disease, you will need to monitor your dog closely as the medications are decreased or discontinued.
Autoimmune hemolytic anemia
Anemia is not a specific disease but rather is a symptom of some other disease process or condition. Anemia is a medical term referring to a reduced number of circulating red blood cells (RBC's), hemoglobin (Hb) in the blood.. Hemoglobin delivers oxygen to the cells and tissues of the body, and a dog who is anemic will suffer from symptoms related to a lack of oxygen.
Normally, red blood cells are produced in the bone marrow and then released into the circulation. When red blood cells age or become damaged, they are removed from circulation and are recycled to form new red blood cells. The number of circulating red blood cells may become reduced if there is a decrease in production of them in the bone marrow, or if there is an increased loss of them from the circulation.
Symptoms include the following.
- Weakness or lethargy
- Weight loss or anorexia
- Increased heart rate and breathing
- Pale mucous membranes on the gums and eyes
- Fever
- Jaundice
- Discoloration of the eyes, gums, and skin
- Collapse, in severe cases
The causes of the disease are unknown, but it appears more frequently in middle-aged female dogs, and certain breeds like Cocker Spaniels and Poodles are more predisposed, though any dog could develop AIHA. Corticosteroids and immunosuppressive drugs are usually prescribed to keep the condition under control. In cases where drugs are not effective, the spleen may be removed. The spleen is responsible for destroying red blood cells that the body deems damaged or no longer useful. Dogs can live a healthy life without a spleen. Rarely, a blood transfusion may be used.
As the disease progresses, excessive levels of bilirubin, a breakdown product of red blood cell hemolysis, build up within the body. Some of this excess bilirubin spills over into the urine, causing it to appear dark. Excessive levels of bilirubin cause the skin, gums and other mucous membranes to appear yellow or jaundiced. The dog may vomit or may have a poor appetite.
Anemia is diagnosed by performing a blood test called a Complete Blood Count (CBC). The CBC measures a number of different values in a sample of whole blood. To test for anemia, the packed cell volume (PCV) will be measured to determine the percent of red blood cells in the sample, the number of red blood cells will be counted, and the cells will be examined under a microscope to determine their size and shape. With AIHA, both the number and percent of red blood cells will be low and the size and shape of the cells will be abnormal. In many cases of AIHA, there will also be evidence of 'autoagglutination' or abnormal clumping of red blood cells.If AIHA is suspected, your veterinarian will also recommend additional diagnostic tests to determine whether the disease is primary or secondary. Tests may include a reticulocyte test to detect the number of reticulocytes (immature red blood cells) that are present in the bloodstream, antibody tests such as a Coombs test, and serologic blood tests to detect certain parasitic diseases.
Immune-mediated thrombocytopenia (ITP)
This happens when the immune system attacks thrombocytes, the cells responsible for forming blood clots. Dogs with this condition will not likely experience a collapse or crisis like they may with AIHA, but it can be a serious condition if there is any bleeding. Here are some of the symptoms you may notice with ITP.
- Bruising
- Excessive bleeding after an injury or surgery
- Excessive bleeding during menstruation
- Blood in the urine or stool
Most dogs with AIHA have severe anemia, and their gums will be very pale rather than the normal pink to red color. Dogs with anemia will be listless and will tire more easily; these symptoms occur because there are not enough red blood cells to carry oxygen to the tissues. The dog may faint or appear disoriented due to low oxygen levels in the brain. To compensate for the lack of oxygen to the tissues, the heart will beat more rapidly and the dog will breathe more rapidly. Treatment for ITP in dogs is similar to treatment for AIHA. A vet will administer corticosteroidsand immunosuppressive drugs. They may remove the spleen, as well. A blood or plasma transfusion may also be helpful. In female dogs, and ovariohysterectomy may be performed to decrease the risk of uterine hemorrhaging during seasons.
The blood profile will evaluate organ function and electrolyte levels, while the urinalysis will measure of kidney function and indicate whether there is any infection in the urinary tract. Chest x-rays help detect or exclude the presence of cancer in the lungs, while abdominal x-rays or ultrasound help detect or exclude the presence of cancer within the abdomen.
How is ITP treated?
If your dog's anemia is so severe that it is life-threatening, a blood transfusion will be needed. Blood samples will be taken for diagnostic testing. The main purpose of a blood transfusion is to stabilize the dog while the underlying cause of the anemia is determined and other treatments can begin to take effect.
Autoimmune diseases of the skin
Autoimmune diseases of the skin in dogs are rare and various. They can be difficult to diagnose and each come with their own set of symptoms. Here are several types of autoimmune diseases of the skin and the signs you should look out for.
- Pemphigus comes in many forms, but commonly results in scaly skin, scabs, or pus-filled sores. Blisters that rupture quickly can also appear. In some forms, these symptoms can sometimes stay confined to the head and feet before spreading elsewhere. The most severe form is pemphigus vulgaris in which ulcers can appear at the mouth, anus, prepuce, nose, and vagina.
- Discoid lupus erythematosis is likely related to SLE, but only affects the face and nose. There may be loss of pigment, scaly skin, or scabby sores around the nose. Ultraviolet light makes nasal scarring worse. Sunscreen and shelter from sunlight are recommended.
- Vogt-Koyanagi-Harada-like syndrome is extremely rare and causes a loss of pigmentation along with eye disease. The nose, lips, eyelids, footpads, and anus turn from black to pink or white, and the eyes become severely infected. Treating it early can prevent blindness.
With skin autoimmune diseases, treatment usually involves the use of topical corticosteroids or low to medium doses of prednisone. Minor cases can require very little treatment, while more severe cases necessitate frequent veterinary visits with strict instructions for application of medication.
Immune-mediated polyarthritis
This can sometimes be seen with SLE or can exist on its own. It covers several specific diseases, but the symptoms in dogs are largely the same. These include the following.
- High fever
- Joint pain or swelling
- Lameness that shifts from leg to leg
- Enlarged lymph nodes
In about half of the cases of immune-mediated polyarthritis, dogs go into remission after being treated with corticosteroids. Cytoxan or Imuran are drugs that are given in the rest of cases and are followed up with steroids. Usually this condition is quite manageable with treatment, and the outlook for dogs that are affected is good.
Other Types Of Treatment For Immune Diseases In Dogs
In addition to medication, some might find a holistic approach helpful when treating autoimmune disorders in dogs. You should discuss these additional treatments with your vet to make sure they are safe for your dog and won’t interfere with other medications. These treatments might include the following.
- Switching to a diet of unprocessed food that hasn’t been treated with chemicals or preservatives.
- Massage by a trained professional that is aware of your dog’s condition.
- Supplements. These may include turmeric, a known anti-inflammatory, or Omega-3, vitamin E, Selenium, and Vitamin C. A probiotic may also be helpful.
- Removal of stress from your dog’s environment, including anything that may cause anxiety.
- Hydrotherapy, which is especially helpful for dogs that may have arthritis symptoms.
- Acupuncture from a trained and licensed practitioner.