Here, we'll take a look at atopic dermatitis.
Now, this is extremely common and must be spoken of why,
because when you talk about atopic type of issues, you've heard of asthma.
And with asthma, majority of your asthmas, are of what type? Oh, yeah, atopic, isn't it?
There is intrinsic as well, but you focus on atopic. So, point is this.
When you talk about atopy or atopic, what does that mean to you?
We're talking about a patient and environment that has been exposed to certain allergens.
And obviously, in the US, we have pollen, pollen, pollen, pollen, whatever it may be.
When you're exposed to that type of allergen,
there's every possibility that you might then elicit a type 1 hypersensitivity
and therefore you would have release of histamine working on H1 receptors,
bringing about bronchoconstriction. That gives you your atopic asthma.
In such patients, you might also have development of atopic dermatitis.
Familiar maybe, maybe unknown.
Associated with asthma, let me stop there and make sure that you're crystal clear about that association.
Often times, as I told you earlier, if your patient is experiencing asthma-like symptoms,
there's every possibility that atopic dermatitis is also part of this.
Also, allergic type of rhinitis. This is called your atopic triad.
Asthma, rhinitis, and dermatitis.
Obviously, immunologically, this is your type 1 hypersensitivity involvement of your helper type 2 T cells.
Atopic dermatitis is a multifactorial disease determined by various ideological factors.
People with atopic dermatitis usually have a family history of atopy, manifesting as asthma,
food allergies, or hay fever.
This familial inheritance has been linked to mutations in the gene for the production of filaggrin.
Although the mechanism is still unclear, sensitization to certain allergens
such as foods can occur during intrauterine life.
Thus, elevated cord blood IgE levels has been linked to a higher risk of atopic conditions.
The hygiene hypothesis also states that early childhood exposure to allergens
prevents the development of atopic conditions.
This explains the higher prevalence of atopic dermatitis in clean westernized countries.
Lastly, a disruption of the epithelial barrier due to structural abnormalities in the epidermis
and chronic immune disregulation may raise the risk of atopy
by increasing susceptibility to irritants and/or allergens.
Demographics, increasing incidence especially in the US.
Most common in childhood and growing out of it is luckily what happens to a child.
So, if there's atopic asthma and there's atopic dermatitis and rhinitis or whatnot,
then the patient, the child, as he or she is growing up, will no longer suffer from it.
That's always good news. What about the morphology?
Highly pruritic, as you can examine. Highly pruritic, as you examine.
And eczematous type of plaque, as you take a look at this closer,
and by that, we mean that the lesion that you're seeing here, these plaques, are eczematous.
We call this weeping type of plaques. And it's itchy, right?
Upon examination further history, the patient's gonna say,
or the child, is gonna itch, itch, itch, itch, itch.
And if you itch enough at some point, my goodness gracious, the plaque, that eczema,
is going to then offer resistance and that --
or should I say, adaptation, and that type of adaptation we'll talk about is called lichenification.
So, it's a story that we'll talk about.
At this point, our topic is atopic dermatitis, just discussed demographics, highly pruritic, and eczematous.
The location of plaque changes with advancing age and this is huge.
So, if you're a child, then think about your aunt who's squeezing you in the cheeks.
"Oh, it's been so long since I've seen you, my boy or my girl."
So, face and extensor surfaces in infants. Think about cheeks and such, in a child.
The eczema that you find in an adult,
you're thinking about the flexural areas in older children and some adults.
The location of your particular eczema with atopic dermatitis which is extremely pruritic,
is going to change based on age. That's important for you to take out of this.
Associations. Well, atopic dermatitis association is a common condition we'll talk about soon enough.
In Greek, we have ichthyosis, and by that, we mean, ichthys, means fishy scaling of the skin.
Other association is keratosis pilaris and another one called Dennie-Morgan lines.
Now, if you take a look at the morphology here of the eczema that I'm showing you,
we have residual eczema on the cheek of this patient and then obviously the flexor areas that you see here.
And these are your weeping type of vesicles and keep in mind that this is itchy atopic dermatitis.
Further morphology here, if you take a look at atopic dermatitis,
it would be more of your weeping vesicles type of appearance in the flexor region, extremely itchy.
The management, education. Meaning what?
Well, if that particular patient or the parents of the child
and which the child is developing atopic dermatitis/rhinitis and asthma, the atopic triad,
then educate the parents or maybe the child to say,
okay, well, maybe perhaps you wanna try to avoid such environments
or be careful about exposure to that particular antigen. Right?
Education. Gentle bathing and generous emollients.
Remember, it's itchy, itchy, itchy, itchy, itchy.
And if you keep itching this and you do not apply any type of, let's say, ointment or emollient,
then at some point in time, that particular plaque might then react or adapt,
and then may become extremely --
well, I don't wanna use the word scarred because in medicine,
we have to call it lichenified or lichenification.
Topical steroids and obviously, antihistamines for that itch
because we're dealing with our type 1 hypersensitivity.
The differentials quickly. Contact dermatitis.
Be careful with the difference.
Atopic dermatitis, exposure to allergens, if that helps you. Allergens, where?
Most likely in the environment.
Hence, in the US, it's a growing field,
so those of you that wish to go onto allergy or you wanna become an allergist,
your practice is going to be filled. Filled.
Because you have tons of patients that are suffering from the atopic triad.
Now, a differential contact, what does that mean? Usually revealed by history.
What kind of history? Well, maybe there was unusual pattern with sharp demarcation,
but the history here, literally, let's say that you have coins in your pocket
and you are "allergic" to that nickel in the coin.
You're wearing your jeans and the jeans are pressing the nickel and the coins upon the skin.
Contact. And therefore, may result in a type 4 hypersensitivity resulting in contact dermatitis.
Hopefully that's clear. We'll talk more.
Quickly, as soon as you say seborrheic dematitis, close your eyes.
Dermatitis. Where? Good, on the face. If it's an adult, tell me about that nasolabial fold.
Is there or is there not involvement of the nasolabial fold in seborrheic dermatitis?
Are you gonna tell me? Yes, there is. Very good. When is it not?
Your malar rash seen with SLE. Are we getting better at this?
If it's an infant, where would you find this? Oh, yeah, cradle cap.
And hopefully if it's mild in an infant,
because of the flaking of the skin on the scalp, good, dandruff.
With dermatitis, more likely involved in the diaper area as well.
Keep that in mind. Okay, seborrheic dermatitis.
Other differentials. Diaper dermatitis, limited to the groin area where atopic dermatitis is unusual.
Groin area is unusual in atopic dermatitis.
Often spares the body folds where feces and urine does not contact the skin.
We'll talk a condition called mycosis fungoides, this is -- let's just put it this way.
I am dissatisfied with the name as should you be. It has nothing to do with fungi.
Nothing. It is a T cell type of cancer. It's a cancer.
So, when the time is appropriate, this is the first time that I've been introducing this to you,
that mycosis fungoides has nothing to do with fungi.
In fact, these are cancerous or should I say, a T cell type of cancer that is in limited to the tissue.
You've heard of Sezary Syndrome.
When the type is right, we'll talk about the two conditions.
At this point, keep it as a differential because of what are you gonna find with atopic dermatitis?
Eczema, erythematous, you might also find this with mycosis fungoides.
Obviously, atopic dermatitis is not at all cancer.
And on top of that, it's uncommon in children.
Mycosis fungoides, often involves the double protected sites beneath the undergarments.
We'll talk further about that. Double protected, so in other words,
something that you feel as though will be protected
and would be then immune to such changes.
Here in this cancer, seriously, everything is susceptible to damage.