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atopic dermatitis or atopic eczema is a
skin rash that's particularly common
among young children but can last into
adulthood atopic refers to an allergy
dirham refers to the skin and itis
refers to inflammation so atopic
dermatitis describes skin inflammation
that results from an allergy more
specifically it happens when the immune
system attacks the skin causing a dry
itchy rash on flexor surfaces of the
body areas like the creases of the wrist
the insides of the elbows and the backs
of the knees as well as exposed skin
surfaces like on the face the hands in
the feet when the immune system
inappropriately starts attacking itself
we call that a hypersensitivity reaction
and there are four types atopic
dermatitis is a type 4 hypersensitivity
reaction and it starts off with
something in the environment called an
allergen like flower pollen
the pollens able to travel through the
slightly porous skin where it gets
picked up by an immune cell in the
tissue just below the immune cell is
called an antigen presenting cell
because it presents a bit of the
allergen to a naive T helper cell
activating it into a th to sell this th
to cell then stimulates a nearby B cell
to start producing IgE or immunoglobulin
e antibodies specific to that pollen
those IgE antibodies bind to the surface
of other immune cells called mast cells
as well as basophils which can be found
in the tissue layer just below the skin
and this process is called sensitization
now let's say there's a second exposure
to pollen that makes its way into the
skin tissue now the allergen can cross
link the IgE on these sensitized cells
resulting in degranulation or release of
a number of pro-inflammatory molecules
like histamine leukotriene x' and
proteases the combined effect of these
molecules is to cause nearby blood
vessels to dilate and become leaky as
well as attract even more immune cells
to the area creating inflammation of the
skin tissue
ultimately this inflammation makes the
skin barrier more leaky potentially
allowing in more of the allergen while
at the same time allowing water to
escape leaving the skin dry and scaly
dry skins very itchy and scratching
further damages the skin barrier
worsening the process in setting up a
vicious cycle of allergy mediated
inflammation dry skin and itching which
characterizes atopic dermatitis
occasionally bacteria can invade the
damaged skin causing even more
inflammation in infants the rash is most
often on the face in the scalp and in
children the rash is usually on the
flexor surfaces of the extremities
atopic dermatitis can worsen in the
presence of allergens like cigarette
smoke mold and dust mites as well as
changes in the weather and even
emotional stress although it usually
causes patches of red itchy skin that
come and go the scheme can occasionally
even blister and peel over time the skin
can become like Hena fide which
literally means turn to leather
itchiness is often worst at night
probably because there are no
distractions
this is often when young children are
most likely to scratch their eczema
lesions because eczema is an autoimmune
mediated process it can't be spread to
other people but since it affects the
skin and therefore the way a person
looks there's still a lot of social
stigma associated with it unfortunately
many individuals especially teenagers
and young adults with atopic dermatitis
suffer from depression and social
anxiety as a result genetics plays an
important role in atopic dermatitis and
these individuals often also have asthma
as well as allergic rhinitis making up
what's called the atopic triad these
illnesses also often run in families
occasionally atopic dermatitis can be
part of a syndrome like hyper IgE
syndrome which has an autosomal dominant
form called Jobe syndrome as well as
phenylketonuria
which is a metabolic disorder that
results from the buildup of the amino
acid phenylalanine and wiskott-aldrich
syndrome which is an x-linked recessive
disease characterized by clinical triad
of eczema thrombocytopenia and
immunodeficiency atopic dermatitis is
generally a clinical diagnosis and there
are ways to help break the cycle of
allergy mediated inflammation dry skin
and itching with regard to allergy
mediated inflammation it's important to
identify and avoid any triggers as well
as avoiding overheating dressing in soft
fabrics and managing stress well which
is of course a good life habit anyways
dry skin can be managed with frequent
moisturization which is usually best to
apply after a lukewarm bath and itching
can sometimes you managed with simple
measures like keeping the fingernails
short and trying to keep children from
scratching but in more extreme cases
there are also steroids and calcineurin
inhibitors both of which aim to dampen
the immune reaction as well as
antihistamines that can help with
itching and antibiotics to help treat
infections if they're needed
all right as a quick recap atopic
dermatitis also called atopic eczema is
a type 4 hypersensitivity reaction in
the skin and is characterized by a cycle
of allergy mediated inflammation dry
skin and itching and most commonly
affects infants and young children
atopic dermatitis can be managed by
minimizing exposure to allergens keeping
the skin hydrated and minimizing itching
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