Lupus is a disease that affects the immune system of a dog by attacking its tissues. There are two types of lupus, and one of them, systemic lupus erythematosus (SLE) can be a frightening disease due to the variety of life-threatening symptoms it can cause. Because of this, it's important for a dog owner to be familiar with SLE and how it is treated.

What Is Lupus in Dogs?

Lupus is an autoimmune (when the body's immune system mistakes its own healthy tissues as foreign and attacks them) or immune-mediated disease (conditions that result from abnormal activity of the immune cells). There are two main types of lupus seen in dogs—systemic lupus erythematosus and the less challenging discoid lupus erythematosus (DLE). Other species, including humans, can also develop lupus, but it is not contagious.

Discoid lupus erythematosus is also known as cutaneous or facial lupus erythematosus and there are also various forms of DLE that affect the skin, nasal planum, and mucous membranes or gums of dogs. A dog will have DLE when the immune system attacks a layer of the cells within the skin to cause the problem. It is not as problematic to a dog as SLE, however.

Systemic lupus erythematosus, on the other hand, affects more than just the external tissues of a dog. SLE attacks the internal tissues and therefore affects multiple body systems and functions. It can vary from dog to dog depending on what part of the body the immune system is attacking but can affect various organs, muscles, the skin, glands, and more.

Symptoms of Lupus in Dogs

Systemic lupus erythematosus can cause an array of symptoms since it can affect so many different parts of the body. The symptoms can slowly or suddenly appear in dogs and the severity of signs also fluctuate over time. With DLE, the only real symptom is the crusting over and scabbing of the skin around the nose and possibly other parts of the skin with disc-shaped patches. Symptoms of SLE can include the following:

Lethargy/Decreased Appetite

Lethargy and a decrease in appetite may be seen due to the overall discomfort and general unwell feeling in dogs with lupus.

Limping That Switches Legs

Lupus can also cause muscle pain which results in a dog limping and crying when attempting to stand or walk. The limping can switch between legs since the muscle pain is often in more than one place and an attempt to pet a dog's leg that has lupus may even result in a dog crying if it is hurting enough.

Skin and Fur Changes

Skin and fur changes are often seen in dogs with lupus. Thinning of the fur and skin, fur loss, a decrease in pigmentation of the skin (a symptom which may also happen with the onset of DLE), and even skin redness can occur.

Skin and Lip Ulcerations

Many dogs also experience ulcerations on the skin and at the corners of the mouth.

Enlarged Lymph Nodes

The dog's dysfunctional immune system may cause enlarged lymph nodes in the neck, armpits, and other regions that can be seen or felt in a dog with systemic lupus erythematosus.

Decreased Muscle Size

The muscles also may appear to atrophy, then shrink and waste over time resulting in muscle atrophy.

Causes of Lupus

The cause of both types of lupus is unknown. With DLE, the triggers that worsen the condition seem to be exposure to ultraviolet (UV) light and cigarette smoke. Medium to large breeds are more susceptible to DLE, including the following dogs:

• Alaskan malamute
• Brittany spaniel
• Chow chow
• German shepherd
• Shetland sheepdog
• Siberian husky

Numerous causes of SLE have been suspected and include genetic factors, physiologic, and even environmental factors. Though SLE is somewhat rare in dogs, some medium to large breeds seem to be prone to developing SLE at around five years of age, including:

• Afghan hound
• Beagle
• Collie
• German shepherd
• Irish setter
• Nova Scotia duck tolling retriever
• Old English sheepdog
• Poodle
• Shetland sheepdog 

Diagnosing Lupus in Dogs

DLE requires a skin biopsy. But, SLE can be very difficult to diagnose due to the varied presentation of symptoms. A veterinarian will begin by performing the following exams and tests for SLE:

• A full physical examination will include obtaining a medical history, checking some blood work, and running urine tests.
• The platelets, white and red blood cell counts, kidney enzymes, protein content in the urine, and other results will be analyzed from these tests.
• X-rays or abdominal ultrasounds are often performed to rule out more common causes of the symptoms.
• An antinuclear antibody (ANA) titer may be performed. if all other diseases are ruled out and the symptoms and test results indicate a possibility of lupus. If this test titer is positive, a diagnosis of systemic lupus erythematosus is made.

Treatment

For DLE, topical treatments are usually used unless severe symptoms require more aggressive systematic medicines. But caring for systemic lupus erythematosus can require various tactics. Special diets, supplements, and treatments may be recommended depending on the specific symptoms being experienced by each lupus patient. Your vet will likely prescribe the following treatments and/or medications to manage the symptoms and suppress the dog's immune system:

• Prednisone
• Prednisolone
• Azathioprine
• Cyclophosphamide
• Surgical removal of the spleen may be necessary if anemia is also present in a dog with SLE.
• If kidneys are affected, a high-quality diet may be recommended. If the kidneys are not severely damaged, the organ function in some dogs are manageable with medications.
  

Prognosis for Dogs With Lupus

The long-term outcome for dogs with DLE is good, but a prognosis for a dog with SLE is difficult to assess with any certainty. Dogs with DLE may need continuous treatment and symptoms may come and go, but your pet can live a normal life.

SLE is progressive and requires lifelong treatment to keep the immune response suppressed. However, suppressing an animal's immune system can have side effects that can also cause serious problems with your dog's health.

How to Prevent Lupus

Since there may be some genetic factors that can cause lupus, dogs that have been diagnosed with systemic lupus should not be used for breeding. Some veterinarians recommend supporting the immune system with various supplements or being careful not to overstimulate the immune system with too many medications or vaccinations at one time or for prolonged periods but there is no definitive prevention plan for lupus.