Atopic dermatitis

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Introduction0:00–1:01

With atopic dermatitis. Dermatitis refers to skin inflammation while atopic comes from the Greek word opia meaning out of place.
This phrase reflects the idea that in atopic dermatitis, the immune system overreacts to everyday harmless substances such as dust and pollen as if they were dangerous, subsequently triggering inflammation and an extremely itchy rash.
Atopic dermatitis also known as atopic eczema is a chronic relapsing skin condition that's particularly common among young Children, but it can also persist well into adulthood.
Now, the skin is the body's natural barrier that protects you from environmental substances like microbes. The outer layer of your skin called the epidermis has four layers stacked up like a protective team at the bottom is the stratum basale followed by the stratum spinosum.
Then the stratum granulosum, the outermost layer and the front line of the skin barrier is the stratum corneum. Think of it as a brick wall in this wall, bricks represent dead flattened skin cells called corneocytes which lock in moisture and keep allergens irritants and microbes out.

Pathophysiology1:01–2:47

But even the strongest wall needs reinforcement. And that's where filaggrin comes in.
This special protein works like rebar inside the wall. It links neighboring cells flattens them out and gives the skin its strength and flexibility at the heart of atopic dermatitis is a complex interaction between genetics, environmental factors and the immune system.
On the genetic side, many individuals have mutations in the gene that encodes filaggrin. Without enough functional filaggrin.
The wall loses its strength and cracks open, leaving our body vulnerable. In other words, the skin loses its ability to retain moisture and keep out harmful substances.
Moreover, this compromised skin barrier opens the door to environmental triggers and allergens such as dust mites and pollen.
But here's the thing, the immune system is always on alert with antigen presenting cells as frontline scouts constantly gathering intelligence on potential threats.
So when something makes its way through the damaged skin, these immune scouts spring into action, they capture the intruder through a process called phagocytosis and break it down.
Next, they present some of its fragments known as antigens on their surface. It's their way of signaling to the immune system.
We have an intruder using these antigens. They alert th two helper T cells to release proinflammatory cytokines called interleukins which signal other immune cells to jump into action.

Symptoms2:47–3:58

Interleukin five activates eosinophils to join the response. While interleukins four and 13 stimulate B cells to differentiate into plasma cells.
Next, these plasma cells begin producing allergen specific IgE antibodies which latch onto mast cells and prepare them for future encounters.
When the body meets the same allergen again the allergen crosslinks the IgE on the surface of mast cells triggering the release of histamine and other inflammatory mediators.
This IgE mediated immune response known as type one hypersensitivity results in the hallmark symptoms of atopic dermatitis, including erythema, swelling and intense itching.
Itching leads to scratching and scratching, makes things worse by further damaging the already fragile skin barrier. Additionally, a sneaky bacterium called staphylococcus aureus takes advantage of the cracked skin.
The bacterium colonizes damaged areas and releases toxins that stimulate the immune system even more, adding fuel to the already raging fire of inflammation.

Causes3:58–4:41

But the immune system doesn't stop at the skin. If a person keeps encountering the same allergen, the reaction can escalate and the immune response can spread beyond the skin.
This occurs when th two cells slip into the bloodstream and travel to the lungs where they can trigger asthma later, they can reach the nasal passages and cause allergic rhinitis.
This step by step progression is called the atopic March. Now, the skin findings vary depending on how long the inflammation has been going on.
In the early acute phase. The skin flares up.
It's incredibly itchy with erythematous and edematous papules and plaques that ooze or form crusts. As the inflammation continues, it shifts into the subacute phase.

Treatment4:41–5:36

In this case, you'll notice erythematous patches or plaques with scaling and crusting. Finally, if the inflammation drags on the condition enters the chronic phase from all the scratching and irritation, the plaques, thicken and skin lines become more pronounced.
This sign is also known as lichenification. In all cases, the skin is so itchy that you'll almost always see excoriations from scratching.
Now, there are several different types of atopic dermatitis. Infantile atopic dermatitis affects babies under the age of two and typically appears after six weeks of age.
It often begins on the cheeks, forehead and scalp, then spreads to the outer parts of the arms and legs and sometimes the trunk.

Summary5:36–8:33

Interestingly, the diaper area and the center of the face are usually unaffected. In this type, skin lesions are typically in the acute phase.
The second type is childhood atopic dermatitis which affects Children from 2 to 12 years of age. This type favors skin folds.
Therefore, it's often referred to as flexural eczema. It typically affects the inner elbows and behind the knees, but it can also affect the wrists, hands, ankles, feet, neck and even the areas around the eyes and mouth.
At this stage, lesions become subacute or even chronic, meaning the skin starts to show signs of lichenification from repeated scratching.
The third type is known as adolescent and adult atopic dermatitis and it appears after 12 years of age. The rash characteristics and distribution mirror the one seen in childhood atopic dermatitis and primarily affects the skin folds, hands, feet, neck and face to diagnose atopic dermatitis.
Several key features must be present first and foremost, is pruritus or persistent itching which often gets worse in the evening and can be triggered by various factors.
These factors include allergens such as mold and dust mites, environmental conditions like extreme temperatures or low humidity as well as irritants including wool, rough fabrics and detergents.
Many individuals also have food allergies which can contribute to skin inflammation and trigger flare ups. In addition to the itching, the person should have erythema dryness or thickened patches that appear in patterns typical for their age group.
Another essential clue is the chronic or relapsing nature of the condition. In other words, symptoms don't just appear once and go away.
They come and go over time, flaring up during certain periods and settling down in between managing atopic dermatitis comes down to good hygiene and staying away from triggers.
People should shower daily for 10 minutes, then gently pat the skin dry right after they should apply an emollient to healthy skin to lock in moisture and use topical corticosteroids on affected areas to calm the inflammation.
All right, it's a quick recap. Atopic dermatitis is a chronic and relapsing skin condition marked by erythema, swelling and intense itching.
Flareups typically occur when the skin reacts to allergens, harsh weather and irritants in infants. The rash usually affects the cheeks, forehead, scalp and the outer sides of the arms and legs.
In older Children and adults, it tends to affect the inner elbows behind the knees as well as the wrists, hands, ankles, feet, neck and around the eyes and mouth.