Lupus in dogs

Lupus in dogs is a disease resulting from a dysfunction of the immune system, which is found in a cutaneous and systemic form.

Although these two forms do not have the same consequences for the animal's health, lupus is always a serious disease that requires veterinary care. To give your pet the best prognosis, it is essential to know how to recognize the signals that should alert you and prompt you to consult a veterinarian.

 

What is canine lupus?

Canine lupus is an autoimmune disease that can affect only the dog's skin or the entire body. It is a relatively rare pathology in dogs. It is called cutaneous lupus erythematosus when the lesions concern only the skin of the animal, and systemic lupus erythematosus when the attacks concern different organs.

Lupus is an autoimmune disease of dogs
Autoimmune diseases are characterized by the body's reaction to produce antibodies against its own cells. In other words, the animal's immune system does not recognize certain components of its body and attacks them as if they were external pathogens.

Autoimmunity can be non-pathological, in which case it is called self-reactivity, or pathological. The latter is referred to as autoaggression, a mechanism that causes injury or functional impairment. The diagnosis of an autoimmune disease is still very complex, because the action of antibodies against the cells of the organism is difficult to demonstrate. It is therefore often a diagnosis that is made by ruling out other hypotheses.

Cutaneous lupus erythematosus of dogs
Canine cutaneous lupus erythematosus is a form of autoimmune dermatosis causing specific lesions, which may be present in other diseases, but are classically associated with lupus. Previously known as canine discoid lupus, a name that has been debated and gradually dropped from veterinary jargon, canine cutaneous lupus erythematosus is also called lupus dermatosis.

It should be noted that its name is currently being changed as scientific knowledge on the subject evolves. The use of the term discoid is discussed, because it refers to a form of lesion in very specific patches which does not correspond to all the clinical manifestations of cutaneous lupus, and which, moreover, is not necessarily caused by the latter.

In fact, lupus does not cause a specific dermatosis, but is involved in various skin diseases in dogs. This relationship between lupus and various dog dermatoses is being studied more and more, and the ulcerative dermatosis of the Collie and the dermatosis of the German Pointer are now linked to this immune disorder. Other types of skin disorders, such as idiopathic ulcerative dermatitis or vesicular dermatitis, also appear to be related to lupus.

Systemic lupus erythematosus in dogs
Systemic lupus erythematosus in dogs, unlike cutaneous lupus, can affect different functions of the body - including the skin. This condition is also called lupus syndrome. It is the most severe form of lupus and has a guarded prognosis. Almost all tissues in the dog's body can be affected by this condition, which can lead to severe and extensive functional impairment, affecting the animal's vital organs.

 

 

 

Causes of lupus in dogs

The mechanisms behind lupus in dogs are still poorly understood, but many hypotheses have been put forward to explain its occurrence. It should be noted that, even if it remains nebulous, canine lupus is a highly studied subject, as this pathology is also found in humans - research in veterinary medicine is always more dynamic when it is likely to bring advances to human medicine.

Today, a familial predisposition is suspected in the first place. In fact, there are clear racial predispositions, with an over-representation of German Shepherds and a high heritability (the incidence decreases when healthy individuals are integrated into a line). Although empirical observations have led to the strong hypothesis that a genetic factor is involved, no gene has yet been formally identified.

The question of infectious transmission has also been raised, with experiments showing that puppies born to a lupus-affected mother and raised away from her did not develop the disease, while those raised in contact with her did. Other studies support this hypothesis - currently controversial - such as the observation of signs suggestive of lupus syndrome in dogs owned by human lupus owners. However, no virus could be incriminated at the moment.

Hormonal factors may also be involved, with systemic lupus erythematosus affecting primarily males, while cutaneous lupus erythematosus affects females preferentially. A study on bats suggests that estrogens may have an aggravating effect, while androgens may have a protective effect.

It also appears that, in humans, lupus occurring before puberty is more virulent than that occurring after menopause, observations that have led to the prediction of the involvement of hormonal factors in dogs by extrapolation. Finally, environmental factors have also been suggested. Certain drugs could be involved in the appearance of lupus (less severe than spontaneous forms), as well as certain toxins, such as heavy metals, silica, asbestos or hydrocarbons.

 

Symptoms of lupus in dogs

The expression of systemic lupus erythematosus in dogs can involve a wide variety of nonspecific symptoms. There is usually an alteration in the dog's general condition, which may include episodes of fever, exacerbated fatigue, respiratory difficulties and neurological disorders.

This deterioration of the organism is the consequence of different pathologies attributable to the self-aggressiveness of the animal's immune system. The destruction of healthy cells by the animal's own antibodies can lead to renal failure, coagulation disorders, pericarditis, myocarditis, lymphedema, neuropathy, inflammatory pneumonitis and pleurisy.

The occurrence of joint and bone symptoms, particularly polyarthritis and polymyositis, is also typical of the disease. The latter are manifested by joint swelling, lameness and synovial effusions, often symmetrical.

The joints affected are preferentially those of the fingers, wrists, hip, elbow and stifle. Finally, skin signs are typical of systemic lupus erythematosus. There are ulcers on the skin and mucous membranes, as well as erosions, scaling, erythema, alopecia and scabs.

The sites of predilection of these cutaneous lesions are the face of the dog, and in particular its ears, as well as the end of its fingers. Cutaneous lupus erythematosus manifests itself only through skin disorders that typically include depigmentation of certain areas, erosion, ulcers and scales.

The nose is often the first or only area affected. The auricles may also be affected, as well as the mucocutaneous junctions and the limbs. It is not always easy to distinguish the symptoms of cutaneous lupus erythematosus from those resulting from systemic lupus erythematosus with cutaneous expression. In general, the lesions caused by cutaneous lupus erythematosus are thought to be less extensive and less severe than those caused by systemic lupus.

 

 

Treatment and prognosis

The diagnosis and treatment of lupus in dogs is tricky, as is still the case with most autoimmune diseases in animals and humans. Much of the diagnosis of the disease depends on ruling out other hypotheses. Biopsies and histological analysis may also reveal biological signs suggestive of lupus.

As with all autoimmune diseases, lupus can be controlled by modifying the body's immune response. Treatment with immunosuppressants or immunomodulators, drugs designed to suppress or modulate the immune response, is usually prescribed. In some cases, anti-inflammatory drugs may act as immunosuppressants.

Cytotoxic drugs may also be considered to eliminate rogue cells that are attacking the dog's body. Their action is relatively similar to that of chemotherapy. Although not widely used in veterinary medicine, dialysis can also be used to eliminate problematic antibodies during acute flares in a lupus dog.

This procedure appears to be successful, but is rarely offered due to cost and limitations. Cutaneous lupus erythematosus is considered less severe, and generally has a good prognosis. The systemic form of lupus is more problematic, the prognosis of the animal remains delicate.

Ultimately, the prognosis of the animal is always conditioned by its response to the treatment implemented.

 

FAQ

Can lupus be treated in dogs?
Lupus is a complex disease that is still difficult to diagnose and treat today. It may be possible to control the symptoms with immunosuppressive drugs, but unfortunately not all dogs respond favorably to this type of treatment.

How do I know if my dog has lupus?
The symptoms of lupus in dogs are not always very specific. There is usually a deterioration in the dog's general condition, joint problems, exacerbated fatigue, neurological problems, episodes of fever and the appearance of skin lesions. As a general rule, it is highly recommended to consult a veterinarian when you notice any change in your pet's health or behavior.

What should I do if my dog has lupus?
If you suspect your dog has lupus, it is essential to take him to a veterinarian who will confirm - or deny - this hypothesis and set up an appropriate treatment.

My dog is itchy and has pimples, does he have lupus?
Lupus is a rare disease in dogs, so an animal with skin disorders is more likely to suffer from another type of dermatosis. However, lupus cannot be ruled out without a veterinarian's opinion. In addition, any skin pathology, lupus or not, should prompt you to consult.

Lupus is as serious a disease in dogs as it is in humans, and veterinary medicine is still struggling to fight it. Like all autoimmune diseases, it occurs when the dog's body turns against itself and attacks its own tissues, causing potentially lethal damage.

Moreover, the absence of specific symptoms makes its diagnosis particularly delicate and often delays its treatment.

However, since lupus is also a disease that affects bipeds, it is the subject of a great deal of research and medical knowledge in this area could therefore rapidly evolve and bring new hope.