Atopic Dermatitis: Skin Allergies

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  • 0:06 Improper Recognition
  • 0:53 What Is Atopic Dermatitis?
  • 1:15 Why Does Atopic…
  • 3:54 Clinical Signs,…
  • 4:19 Treatment and…
  • 5:13 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson will define atopic dermatitis, as well as explain how filaggrin plays a role in its development. We'll also review the different signs and symptoms of atopic dermatitis, as well as the ways this condition can be treated.

Improper Recognition

I'm going to tell you a little story. But don't try it at home because you may get bit. One day, I snuck downstairs in my parents' home and noticed my dog was sitting quietly, looking out the window in peace. Being a bit of a prankster, I decided to have some fun and quietly snuck back upstairs where I put on my very scary Halloween mask. As it tiptoed back down, I got to within a few feet of my dog and said her name, 'Mocha!'

As she turned around and saw me, she freaked out, started barking, and nearly attacked me in self-defense. Once I pulled my mask off she immediately calmed down. The way my dog didn't recognize me and almost attacked me is very similar to the way your own body may sometimes cause you harm, as we'll soon learn.

What Is Atopic Dermatitis?

Some people, especially children, are predisposed to developing an itchy, non-contagious, and long-term inflammatory skin condition known as atopic dermatitis or atopic eczema. We are pretty sure that genetic traits, perhaps even heritable genetic traits, can predispose an individual to developing this condition as a child, and sometimes even as an adult.

Why Does Atopic Dermatitis Occur?

But there's more to it than that. You see, these genetic defects combine with things in the environment that may cause this reaction. Dirt, pollen, dust, chemicals in soaps or moisturizers, and even food can trigger atopic dermatitis. Let's explore one key hypothesis as to how our genes and environment act together to cause people with atopic eczema so much trouble.

Scientists have found that some individuals with atopic dermatitis have a mutation in a gene that codes for filaggrin. Filaggrin is a protein responsible for maintaining the architecture of the skin and for keeping it hydrated and protected. When the filaggrin proteins are unable work properly due to a genetic defect, the skin becomes dry and cracked. This allows for the entry of allergens into the deeper layers of the skin and body.

It's kind of like when watering pipes running under the ground stop working or you don't use moss to insulate your potted plants and earth begins to crack from a lack of hydration, well, the same thing happens here. Once these allergy-inducing molecules enter the body through these cracks, the body over-reacts to their presence by secreting molecules that trigger inflammation, which causes the redness, swelling, and itchiness associated with atopic dermatitis. This inflammatory process, in turn, causes the skin to crack and dry more, which causes more allergens to enter, leading to a viscous cycle.

What I want to re-iterate is that in people with atopic dermatitis it's not just about filaggrin. I don't want you to get hung up just on that. That's because there are plenty of people with no such mutation who suffer from this problem. An over-reactive immune system, involving T-cells, plasma cells, mast cells, cytokines, and antibodies, is just as an important part of this malady as anything else.

Let me put it to you this way - you may be a person who has a crack in their skin and even have allergens entering into that crack, but that doesn't mean you'll develop a serious allergic reaction to it. People with atopic dermatitis have an immune system that over-reacts to something that isn't as scary as it looks. Just like my dog over-reacted to my Halloween costume, even though it was really innocent little old me underneath it, so too does your immune system over-react to sometimes perfectly innocent things only because it interprets them as scary-looking threats, when they're actually not.

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