Is Psoriasis an Autoimmune Disease?

Reviewed by: HU Medical Review Board | Last reviewed: July 2016.

Autoimmune diseases are disorders caused by abnormal functioning of the immune system. There are many potential causes of autoimmune disorders. Most research points towards a combination of genetic, environmental, and other factors1.

An autoimmune disorder occurs when our immune system attacks and destroys healthy body tissue by mistake. There are more than 80 types of autoimmune disorders, and plaque psoriasis is on the list.

What is an autoimmune disease?

When you have an autoimmune disorder, your immune system does not distinguish between healthy tissue and antigens. Antigens are substances that are recognized by your body as foreign (e.g. bacteria, viruses, toxins).  Your immune system normally produces antibodies, which are protective substances, in response to antigens.

Antibodies enable other protective responses and signal your body’s immune system to destroy the foreign invaders. In the case of autoimmune disorders, your body does not respond appropriately and sets off a reaction that destroys normal tissues.

There are key proteins produced by your body that regulate specific immune responses. The function of these proteins is to mobilize other cells or molecules in an organized way. These key responses are also referred to as pathways of inflammation5.

In autoimmune diseases these proteins either fail to signal in the correct way or signal too frequently, causing chronic levels of inflammation.

Scientific understanding of various components of our immune system and their regulatory functions has increased dramatically in the past two decades2. Yet there is still a lot of research needed to develop effective treatment options.

The goal of current research is to understand the genes and molecular mechanisms that cause autoinflammatory and autoimmune diseases so that researchers can then design better ways to treat these conditions.

How are autoimmune diseases diagnosed?

Research identifying autoimmune disorders and the scientific understanding of how aspects of our immune system work is constantly evolving3. This frequently makes it challenging for your health care provider to know if you have an autoimmune disease, and if so which one.

Getting a definitive diagnosis can take time and be frustrating. One of the classic signs of autoimmune disease is chronic inflammation.  Inflammation can cause redness, heat, pain and swelling either in specific parts of your body or all over.

Autoimmune diseases often have periods when symptoms get significantly worse, or flare-ups, and periods of remission, when symptoms significantly lessen or seem to disappear. Even though you may not be experiencing a flare-up, your body can still be impacted by the chronic inflammation and you may experience other symptoms like fatigue as a result.

While treatment options depend on the disease, one of the most important treatment goals is to target the specific inflammatory pathway believed to be most important to the disease symptoms.

How is psoriasis considered an autoimmune disease?

For much of history, psoriasis has been seen as a disease of the skin. It is now clear that psoriasis is an autoimmune disease that impacts many systems of the body, involving multiple inflammatory pathways, with a primary presentation affecting the skin4.

This inflammation can also affect the joints, vascular system, and eyes of people with psoriasis.

Psoriasis is the most common known human autoimmune disease, found in approximately 2-3% of the general population.

Several dozen gene locations have been identified that are believed to be involved in the development of psoriasis3. These genes are known to affect innate immunity, cell signaling processes, and skin barrier function.

These studies also provide more evidence that people with psoriasis may be genetically predisposed to other autoimmune diseases5.

With psoriasis, the body's immune system goes haywire, sending out faulty signals that speed up the growth of skin. The way psoriasis affects the skin is primarily driven by a type of white blood cell called a T cell, as well as myeloid dendritic cells2. Normally, T cells help protect the body against foreign invaders.

Inflammatory myeloid dendritic cells release specific proteins to activate T cells. These T cells are then put into action by mistake and become so active that they trigger other immune responses, which lead to chronic inflammation and to the rapid turnover of skin cells5.

How does it affect psoriasis treatment options?

The primary goals of treatment are to:

  • Reduce symptoms
  • Control the autoimmune process
  • Maintain the body's ability to fight disease

For people with moderate to severe plaque psoriasis, an immunosuppressive drug may be needed to reduce their immune system's abnormal responses. Your healthcare provider may prescribe medication that is designed to affect processes of inflammation throughout your entire body, like a corticosteroid.

In other cases, your healthcare provider may choose a therapeutic biologic medication that is designed to target a specific inflammatory pathway.

Combining biologics with traditional psoriasis therapies may provide an important treatment option for people who do not adequately respond to monotherapy. These approaches are called combination therapy.

Combination therapy may also help in the prevention or treatment of co-occurring diseases (psoriatic arthritis, inflammatory bowel disease) in certain patients.

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