Rare Autoimmune Skin Diseases - When Body Fights Itself

The immune system in our body is our best defence against "foreign" substances such as bacteria and viruses. If it were not for our immune system, our health would be susceptible to the multitude of microorganisms that exist in our environment. The failure of the immune system to recognise, "foreign" substances and those, which belong to the body, leads to autoimmune diseases. Some skin diseases are also a part of autoimmune diseases.

In this article, we will review the immune system and how autoimmune diseases can be caused, focussing only on autoimmune skin diseases. The article also explores some rare autoimmune skin diseases.

What are Autoimmune Diseases?

The immune system of our body is its defence mechanism. It protects us against microorganisms such as bacteria and viruses that are not native to our body.

When our body comes into contact with a harmful bacteria or virus in the environment, the immune system produces substances called antibodies to attack these foreign substances. Antibodies are proteins that expel the hostile foreign microorganisms from our body. This mechanism also works for skin diseases.

Antibodies are produced in response to a specific threat. The substance, which provokes the production of an antibody, is called an antigen. The substances against which antibodies are produced may be bacteria, viruses, worms, tissues and organs received during transplantation.

Sometimes, our immune system fails to differentiate between a foreign antigen and substances native to the body. Our immune system then produces antibodies against the body's own cells, tissues and other substances.

When the immune system ends up mistakenly fighting constituents of the body, it is known as an autoimmune disease. If the immune system is acting against skin cells, it results in autoimmune skin diseases.

How are Autoimmune Skin Diseases Caused?

What makes our immune system attack its own skin cells? Some causes identified for this type of an autoimmune response are:

• Genetic causes - Some autoimmune diseases and autoimmune skin diseases are more prevalent in certain population groups. They can also run in families. It has been found that Hispanic and African-American women are more prone to autoimmune diseases affecting the skin.
• Lymphocyte disorder - B Lymphocytes are white blood cells which produce antibodies. If Lymphocytes themselves do not function as they should, they can produce antibodies that attack healthy skin cells.
• Intruder microorganisms similar to body cells - Sometimes, the bacteria or virus that infects the body may be similar to a body skin cell. Then the immune system not only attacks the intruder but also healthy skin cell.

Some Autoimmune Common Skin Diseases

Some examples of relatively common autoimmune diseases affecting the skin are Alopecia areata and Lupus erythematosus.

In Alopecia areata, the immune system of the body attacks hair follicles on the scalp, causing hair loss in the affected area. Hair starts falling out in round clumps in the scalp. In rare cases, it may lead to Alopecia universalis, where there is hair loss in eyelashes, eyebrows and body.

Genetic causes are said to be the cause of Alopecia areata.

In Lupus erythematosus, antibodies affect healthy tissues throughout the body. Parts affected may include skin, joints, kidney and the heart. Skin diseases such as Discoid lupus dermatitis affects the skin only and does not impact any internal organs.

Symptoms of Discoid lupus include red rashes on the cheeks and sensitivity of the skin to sunlight.

Women are more prone to Lupus than men. While genetic causes can be a reason, Lupus can also be due to medication reaction or viral infection.

Autoimmune Rare Skin Diseases

Some rare skin diseases are due to an autoimmune response of the body.

In certain types of rare skin diseases such as autoimmune blistering diseases, the proteins needed for skin layers to stick together are attacked.

Here are some examples of autoimmune rare skin diseases

Bullous Pemphigoid

This is a type of autoimmune blistering disease where antibodies attack parts of the basement membrane of the skin. The basement membrane separates the top layer of the skin, the epidermis and the dermis layer below. As the skin layers or cells become detached, blisters develop.

This is a chronic condition where the blisters cover large areas of the skin, and do not heal by themselves. Itching is common.

Pemphigus

Pemphigus is one of rare blistering skin diseases where epidermal skin cells such as Keratinocytes, cannot be attached to each other. Normally Keratinocytes adhere to one another through substances in our skin called Desmosomes. In Pemphigus, the immune system attacks Desmosome function.

Symptoms include blisters on the skin, mucous membrane and on the mouth.

The most common type is Pemphigus Vulgaris. Causative factors can be hereditary.

Epidermolysis Bullosa Acquista (EBA)

This is an acquired version of the skin disease Epidermolysis Bullosa. It is a very rare skin disease.

In Epidermolysis bullosa acquista, the immune system produces antibodies against a type of collagen, Type VII collagen, found in the skin layers. Type VII collagens are a part of a substance known as anchoring fibrils which again play a role in attaching skin layers.

There is formation of blisters both beneath and on the top layer epidermis accompanied by pain.

Treatment and Resources for Autoimmune Skin Diseases

Autoimmune skin diseases are treated by suppressing the immune system using specific medication. Drugs, which suppress the immune response of the body, are known as immunosuppressants. Some examples of immunosuppressants are cyclosporine, azathioprine and methotrexate.

Using immunosuppressant drugs can however weaken the natural defence system of the body and may lay the body prone to more common infections and diseases, even cancer.

Corticosteroids, which are drugs mimicking human hormone Cortisol, can also be used for treatment.

These types of diseases affecting the skin may be chronic and may need prolonged treatment.

Some online resources for skin diseases such as DEBRA for EBA and pemphigus.org can provide comprehensive guidance and information.

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