Systemic lupus erythematosus (SLE) in dogs is a disease where the immune system attacks the skin, blood cells, nervous system, joints, and internal organs. It can be a scary diagnosis to receive. To help you understand this condition, integrative veterinarian Dr. Julie Buzby discusses the causes, symptoms, diagnosis, treatment, and prognosis for SLE in dogs.
The immune system functions to protect your dog’s body against foreign invaders (bacteria, viruses, parasites, etc.) as well as dangerous changes in normal cells within the body. However, sometimes the immune system attacks a dog’s own cells and tissues by mistake. The resulting disease is called an immune-mediated or autoimmune disease.
One specific immune-mediated disease in dogs, systemic lupus erythematosus (SLE), is often called “the great imitator.” This is because the common symptoms of SLE in dogs are nonspecific. In other words, they could be present due to a variety of possible disease processes.
What is systemic lupus erythematosus (SLE) in dogs?
Systemic lupus erythematosus (SLE) in dogs is an uncommon, generalized autoimmune condition in which the immune system attacks the skin, blood cells, joints, nervous system, and multiple internal organs. As a result, the body may start to destroy its own red blood cells, white blood cells, and platelets. Plus, when the immune system targets the joints, skin, and other organs, it can cause significant inflammation and damage.
Which dogs tend to develop SLE?
Dogs affected with SLE are usually around five years old when symptoms first appear. But cases of SLE have been diagnosed in puppies as young as six months of age. Male dogs may be slightly more likely to develop SLE than females, although opinions are mixed on whether gender truly plays a role.
Several dog breeds are predisposed to developing SLE. Most are medium and large breeds, including:
- Afghan Hounds
- Beagles
- Collies (rough-coated)
- German Shepherds
- Irish Setters
- Nova Scotia Duck Tolling Retrievers
- Old English Sheepdogs
- Shetland Sheepdogs
- Poodles
What causes SLE in dogs?
There are a number of factors that can contribute to the onset of systemic lupus erythematosus in dogs. As mentioned, we know there is a genetic predisposition in certain breeds. Other possible causes include environmental factors like allergies, infections, medication reactions, or abnormal thyroid hormone levels. Since symptoms are often worse for dogs in the summertime or for those who spend lots of time outdoors, exposure to intense UV light may also play a role in the development of SLE.
What are the symptoms of systemic lupus erythematosus?
Clinical signs of SLE in dogs vary widely due to the generalized nature of the disease. Some symptoms involve the body as a whole. Others are related to the specific body system the immune system is targeting. Unfortunately, many of these symptoms may wax and wane, which makes diagnosing SLE more challenging for your vet.
Generalized symptoms
Some of the whole-body symptoms of SLE include:
- Fever: If you take your dog’s temperature, it may be higher than 102.5oF, which constitutes a fever. Often, the fever may come and go rather than being present all the time.
- Low energy: Being a lethargic dog is common. Your dog may lie around more or not want to play like usual.
- Loss of appetite: Because of the fever and/or painful oral ulcers, your dog may not want to eat.
- Weight loss: Over time, dogs may lose weight if they aren’t eating enough.
- Lymph node enlargement (lymphadenopathy): You may see a lump over your dog’s lymph node locations, or the lymph nodes may feel larger than normal.
Symptoms related to the effects of SLE on blood cells
The body may attack and destroy the platelets, white blood cells, or red blood cells.
Bleeding due to low platelets
Since platelets play a large role in blood clotting, low platelets in dogs (thrombocytopenia) may lead to bruises on your dog’s skin. Additionally, some dogs may experience bleeding in other locations, like the chest, abdomen, GI tract, or dog nose bleeds.
Increased risk of infection due to low white blood cells
Dogs with low white blood cell counts (leukopenia) may be lethargic and weak. Plus, since white blood cells are important for fighting infection, leukopenia may increase the risk of your dog developing secondary infections.
Weakness and lethargy due to low red blood cell counts (anemia)
Low red blood cell counts (anemia in dogs) can occur in 30-60% of dogs with systemic lupus erythematosus. It may either be a result of chronic disease or immune-mediated hemolytic anemia (IMHA in dogs). These dogs often experience pale gums, weakness, and lethargy due to the decrease in the number of circulating oxygen-carrying red blood cells.
Skin problems
Changes to the skin occur in 46% of dogs with SLE. This tends to be one of the main reasons dogs with SLE end up at the vet. Possible skin problems include:
- Blisters and painful ulcers: Ulcers may be located at the mucocutaneous junctions (areas where haired and non-haired skin meet, like the lips), elsewhere on the skin, or in the mouth.
- Generalized redness of the skin: Increased redness is easiest to see where the hair is thin, but it can be present all over the body.
- Thinning hair: You might notice your dog losing hair or the coat looking more sparse.
- Loss of normal skin pigmentation, especially on the face (eyes, nose, lips): These areas may lose their typical dark coloration and become more pink or white.
- Scaling or crusting of the skin: Instead of being smooth, your dog’s skin might have flakes or crusts.
- Itchiness: Some dogs itch various parts of their bodies.
Limping due to joint and muscle pain
Seventy-eight percent of dogs with SLE develop arthritis in multiple joints (polyarthritis). This can lead to the dog limping, not jumping up or climbing stairs as much, or lying down more often. The dog may also experience shifting leg lameness, meaning it seems to jump from one leg or joint to another.
Additionally, muscle pain (myalgia) can contribute to limping and a stiff gait in dogs with SLE. Often, lameness is the other reason that dogs with SLE first go to the vet.
Kidney damage
The immune response can damage the kidneys, leading to inflammation and loss of protein in the urine (proteinuria). This occurs in 55% of dogs with SLE.
At first, changes will be evident on a urinalysis. However, as the kidney damage progresses, you may start to see signs of kidney disease in dogs, such as increased thirst, increased urination, and vomiting.
Heart and lung problems
Inflammation of the lining of the chest cavity (pleura) and the heart (pericardium) is possible. Plus, dogs could go into respiratory distress as fluid accumulates in the chest cavity (pleural effusion) or lungs (pulmonary edema).
Sometimes fluid may also build up in the sac around the heart (pericardial effusion), making it hard for the heart to work effectively. This can lead to a pot-bellied dog appearance from the accumulation of fluid in the abdomen, plus weakness and collapse.
Neurological changes
Some dogs may experience cognitive decline, perception of normal touch as painful (hyperesthesia), seizures in dogs, or other neurological issues in dogs.
How will the vet diagnose a dog with SLE?
Diagnosing SLE requires a combination of active symptoms, blood test results, and findings on other diagnostic tests that are compatible with SLE. There isn’t one single test that says “yes” or “no.”
Some vets may use a proposed classification scheme in which a patient meeting three or more of the following criteria would be considered to have SLE:
- ANA positive
- Skin changes that fit with SLE, such as crusting, ulcerations, or depigmentation
- Oral ulcers
- Arthritis in two or more joints (polyarthritis) that is nonerosive
- Kidney issues (proteinuria) without a UTI in dogs
- Low platelets and/or low red blood cells without a known trigger
- Low white blood cells
- Inflammation of multiple muscles (polymyositis) or the heart muscle (myocarditis)
- Serositis (inflammation of the thin membrane covering the inner surface of the chest and abdomen and surrounding the heart)
- Neurological changes
- Antiphospholipid antibodies
The vet may carry out the following tests to obtain the information necessary to reach a diagnosis of SLE. (For an example of how the diagnostic process works in a real-life scenario, check out this case report of a German Shepherd with SLE published in the Journal of the American Veterinary Medical Association (JAVMA).)
Physical exam
During the exam, the veterinarian may notice joint pain or swelling, changes to the skin, ulcerations, abdominal swelling (due to fluid or organ enlargement), bruising, or other symptoms discussed previously.
Lab tests
There are several blood tests for dogs that the vet might recommend:
- CBC (complete blood count): Dogs with SLE may have decreased red blood cells, increased or decreased white blood cells, and/or decreased platelets.
- ANA test: This blood test identifies the presence of anti-nuclear antibodies in circulation. The antibodies can be present in other inflammatory diseases, drug reactions, or certain types of cancer, so it’s necessary to consider the symptoms and CBC results in conjunction with the ANA test result for an accurate SLE diagnosis. If your dog has a positive ANA test, but no other symptoms or bloodwork to confirm SLE, there’s a good chance that this is a false-positive result.
- Chemistry panel: While nothing on the chemistry panel distinctly points to SLE, the vet may suggest it as a way of getting a picture of your dog’s overall health. Plus, it helps evaluate the organs that SLE may attack and rule out other conditions that may have similar symptoms.
Additionally, the vet may run a urinalysis. This is a good way to look for evidence of protein in the urine and to help rule out a UTI or other urinary tract problems.
Imaging studies
The vet may use X-rays and ultrasound to help identify enlarged internal organs (usually the liver and spleen). Imaging is also useful for detecting areas of abnormal fluid accumulation in the joint space, the chest cavity, or in the thin sac (pericardium) that surrounds the heart.
This information will help your veterinary team determine if they need to collect fluid samples from any of those locations.
Fluid analysis
Joint taps (arthrocentesis) in dogs with SLE may reveal increased numbers of white blood cells or LE cells (lupus erythematosus cells—white blood cells with a specific appearance) in the joint fluid. This confirms the presence of an inflammatory process like SLE.
Collecting a fluid sample from the chest cavity or airway may also reveal the presence of LE cells. However, this is an uncommon finding in dogs.
What is the treatment for SLE in dogs?
If the vet diagnoses your dog with SLE, the main goals of treatment are suppressing the immune system so that it doesn’t continue to mount an abnormal response, and keeping your dog comfortable.
Using medications to suppress the immune response
Immunosuppressive doses of steroids (prednisone for dogs) or other immunosuppressant medications like azathioprine or cyclosporine are often the first line of defense in treating SLE. Regardless of the exact protocol, dogs with SLE usually continue treatment for at least six months before the vet attempts to taper these medications to the lowest effective dose.
Warning: Abruptly discontinuing steroids can lead to significant side effects for your dog. Thus, be sure to speak with your veterinary team before stopping any medications.
Managing the symptoms
Additionally, your vet will recommend medications, supplements, and routines that help your dog feel better.
Controlling pain
Pain medication can provide relief if SLE has made your dog’s joints painful or caused muscle pain. However, if your vet prescribed steroids to treat SLE, you’ll need to avoid giving other anti-inflammatory medications like NSAIDs (such as carprofen for dogs or meloxicam) at the same time.
Not combining steroids and NSAIDs helps protect your dog from gastrointestinal upset and stomach ulcers in dogs. Safer pain medication options to discuss with your vet include gabapentin for dogs, pregabalin, and amantadine for dogs.
There are also a variety of options for natural pain relief for dogs.
Using supplements to support your dog’s skin
Especially if your dog has skin symptoms, anti-inflammatory supplements may help your dog feel better. Vitamin E and fatty acid supplementation (omega-3 fatty acids for dogs) are effective for decreasing inflammation in the body and nourishing the skin. Plus, some dogs with autoimmune skin diseases benefit from the combination of tetracycline (an antibiotic) and niacinamide (a specific B vitamin).
Your veterinarian can recommend safe, reputable supplement brands that you can add to your dog’s daily mealtime or treat routine.
Avoiding UV light
Since SLE symptoms may get worse with exposure to UV light, keep your dog out of bright sunlight. Also, apply dog-safe sunscreen before enjoying outdoor activities. (Human sunscreen may contain toxic ingredients, so only use sunscreen formulated for dogs.)
Taking other measures as dictated by the symptoms
Additional medications or a transition to specialized diets may be necessary if other organ systems, like the kidneys, are also involved.
Contact your vet if you have concerns during the treatment process
It’s important to let your vet know if your dog experiences any side effects from treatment. The goal is to help your sweet dog feel better, not worse. Your feedback helps the veterinary team adjust the plan to keep your dog feeling as good as possible.
Palliative care for dogs with SLE
In the event your dog doesn’t respond well to any treatment protocols, you can also discuss palliative care options with your vet. Palliative care focuses on maintaining your dog’s comfort and quality of life for the remainder of the time you have together. There are vets who specialize in hospice care for dogs. Or you can speak to your regular vet about how best to help your dog.
What is the outlook for dogs with systemic lupus erythematosus?
Because SLE can damage so many different organ systems, the prognosis is often poor to guarded due to the risk of organ failure. In fact, as many as 40% of dogs with SLE may die within a year of diagnosis despite aggressive treatment protocols.
There is no cure for SLE, so lifelong therapy is necessary to manage symptoms and relapses. Unfortunately, due to the immunosuppressive nature of SLE treatment, there is an increased risk of secondary infections. This is the case because your dog’s immune system is unable to mount the necessary response to attack foreign bacteria, viruses, and fungi.
Partner with your veterinary team
If your dog was recently diagnosed with systemic lupus erythematosus, it’s understandable that you would have lots of questions for your veterinary team. Don’t hesitate to ask them or to speak up if you have concerns. Keeping those lines of communication open is vital as your dog moves through his or her treatment journey.
While the future may seem scary, remember that the veterinary team is in your corner. They can help with whatever you and your dog need along the way.
Has your dog been diagnosed with SLE?
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