Autoimmune diseases in dogs – when the body attacks itself

If your dog’s immune system attacks his body it can cause autoimmune diseases. Learn key signs and natural ways to support his immune health. 

Your dog’s immune system protects him from disease and keeps him healthy, but it can sometimes malfunction. Genetic and environmental factors can trigger immune dysfunction, leading to autoimmune reactions. This article explores autoimmune diseases in dogs and the health issues they can cause. 

Immunity against self

Two cellular systems in the body provide and maintain immune competence. They involve a type of white blood cell called lymphocytes. These cells have specialized immune functions, including:

• Those of the circulating blood or humoral immune system — derived from B-lymphocytes or B-cells (from the bone marrow)
• A cellular or cell-mediated immune system — derived from T-lymphocytes or T-cells (from the thymus gland).  

The term “autoimmunity” literally means immunity against self. It’s caused by an immune-mediated reaction to self-proteins or antigens (i.e. failure of self-tolerance). Genetic factors can make humans and animals susceptible to autoimmune disease. Numerous viruses, bacteria, chemicals, toxins and drugs can trigger autoimmune reactions in susceptible individuals. 

This mechanism most often operates through a process called “molecular mimicry.” A foreign substance mimics a body component, causing antibodies to target both. The resulting autoimmune disease reflects the sum of the involved genetic and environmental factors. 

Autoimmunity is most often mediated by T-cells or their dysfunction. According to a landmark review, “perhaps the biggest challenge in the future will be the search for the environmental events that trigger self-reactivity” (Sinha, Lopez and McDevitt, Science, 248: 1380, 1990). 

Genetically-based autoimmune diseases

The list of documented heritable autoimmune disorders in humans and animals is alarming and continues to grow as we damage and pollute our environment. 

• Endocrine – thyroid (thyroiditis), adrenal (Addison’s disease), pancreatic (diabetes)
• Hematologic – erythrocyte (AIHA, IMHA), platelet (IMTP), leukocyte
• Muscle — myasthenia gravis, masticatory muscle myositis, polymyositis, dermatomyositis, multiple sclerosis      
• Eye — keratoconjunctivitis sicca (dry eye), uveitis, pannus, uveodermatologic syndrome (VKH)
• Skin — pemphigus disorders, systemic lupus erythematosus, vitiligo 
• Neurologic — immune-complex meningoencephalitis, Alzheimer’s disease
• Renal — immune-complex glomerulonephritis, systemic lupus erythematosus (SLE)
• Joint — rheumatoid arthritis

Hematologic diseases

Immune-mediated hematologic diseases include hemolytic anemia (AIHA, IMHA) and/or thrombocytopenia (low platelet count, IMTP). Doctors and researchers are reporting these diseases more frequently in both animals and humans. In dogs, bone marrow failure can accompany this disorder. Prognosis is guarded to poor, with reported mortality rates between 28% and 70%.

Fast fact: Affected dogs have one or more of these signs: lethargy, anorexia, pale mucous membranes, weakness, exercise intolerance, rapid heart rate, rapid breathing, jaundice, hemoglobin pigment in urine, and fever. 

Laboratory tests may show red cell auto-agglutination, positive Coombs’ test, spherocytosis (rounded red blood cells), thrombocytopenia and neutrophilia (low neutrophil count). 

Anemia may be regenerative or non-regenerative depending on the duration of illness and immunological targeting of red cell precursors in the bone marrow. Some dogs may also have other autoimmune diseases. 

While many cases have unknown causes, veterinarians may identify a recent stress event as a potential trigger. These events can include vaccination, drug, chemical or toxin exposure, surgery, hormonal change, and infection or injury within the previous 30 to 45 days. 

Many breeds show increased risk for IMHA, and veterinarians consider the American cocker spaniel at highest risk. Mixed and hybrid breeds can also be affected, and females are more commonly affected than males.  

Addison’s disease 

Also called hypoadrenocorticism, Addison’s disease results when the adrenal glands are underactive and do not produce enough adrenal cortical hormones. In the primary form of Addison’s disease, the dog’s lymphocytes progressively destroy the adrenal glands through a self-directed immune reaction.

Addison’s disease can cause many serious health issues and is often misdiagnosed as other disorders. Symptoms are non-specific and mimic other general conditions. They include muscle weakness and general lethargy. Affected dogs may be unable to jump on furniture, have trouble climbing stairs, lie down a lot, or lack enthusiasm for physical activities. 

Dogs may also experience vomiting and diarrhea. Other signs include hyperpigmentation (small dark patches on the skin or mucous membranes), poor appetite, joint pain, shivering, and muscle tremors.

When combined with autoimmune thyroid disease, the condition is called Schmidt’s syndrome. Once diagnosed, the treatment options for Addison’s disease are very effective, but require medication for the rest of the dog’s life.

Fast fact: At least a dozen breeds are predisposed to Addison’s disease. Researchers have defined inheritance in several, such as the Portuguese water dog, standard poodle and Nova Scotia duck tolling retriever. Again, females are more commonly affected than males. 

Alternative approaches to managing and treating autoimmunity

Veterinarians can augment or replace standard treatments with holistic alternatives. Rather than suppress the immune system with corticosteroids, we can use alternative means of down-regulating the cytokines (cellular enzymes) that trigger cell-mediated immunity. 

• Some clinicians use biologically active glandulars such as multiple glandular supplements or thymic extract protein. 
• Other treatments that balance and modulate the immune system and offer immune support include plant sterols and sterolins (from fruits and vegetables), bioactive botanicals (plants and herbs), and medicinal mushrooms. 

Fast fact: Treatments should also aim at assisting the liver’s detoxifying pathways — e.g. with milk thistle and SAMe – and increasing the amount of protective amino acids by supplementing with glutathiones, cysteine and taurine. 

• Vets and dog parents can use antioxidants like vitamins A, C, D and E, selenium, bioflavonoids from vegetables (e.g. red bell peppers, broccoli, Brussels sprouts, spinach), fruits (e.g. blueberries, cranberries, pomegranate) and herbs (e.g. oregano, garlic, turmeric) to strengthen the dog’s metabolism and immune system. 

You can also help manage autoimmune diseases in dogs by providing good nutrition and reducing exposure to toxins (see sidebar on page xx). Though these conditions are becoming more common, awareness, proper healthcare, and regular checkups will do a lot to protect your pooch. 

Four main causative factors in autoimmunity

1. Genetic predisposition
2. Hormonal influences, especially sex and thyroid hormones
3. Infections, especially viruses; drugs and chemical exposures
4. Stress — physical, physiological, psychological

Managing autoimmunity in your dog 

1. Good nutrition helps dogs with autoimmune diseases withstand environmental challenges. The results have been remarkable. The food must be of good quality, preferably of relatively low bio-available protein content (22% to 26%) and grain-free (without wheat, corn or soy). 

Increasing carbohydrate and reducing protein, while maintaining high-quality protein, benefits many affected dogs. This approach helps balance the immune system and increase disease resistance.  

2. Avoiding or minimizing toxin exposure is equally important. Toxins include pesticides, chemical fertilizers, radiation, and high-tension powerlines. They also include over-vaccination, preventive chemicals for heartworm, fleas, and ticks, and certain drugs (e.g. potentiated sulfonamides, sex hormones) that can worsen immune disorders. 

With your veterinarian’s guidance, you can use alternative strategies to protect your dog from common infectious diseases. These include periodic serum antibody vaccine titers and natural methods to prevent heartworm, fleas, and ticks.

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