Pathophys - Atopic Dermatitis Flashcards
true or false
atopic dermatitis is not chronic
FALSE - it is
in remission, it is true that the damage may completely heal and look normal, but the condition is still chronic in that it will always respond to whatever triggered it
explain what skin affected by atopic dermatitis will look like
itchy
red
swollen
may crack
true or false
in atopic dermatitis, the damage is not very pronounced
TRUE
really just affects the surface of the skin
explain some features that can be seen microscopically in atopic dermatitis
epidermal intercellular edema
dermal inflammatory infiltration of leukocytes
endothelial cell hypertrophy
basement membranes thicken
venules altered
increased number of Langerhan’s cells – enhancement of phagocytic cells in skin
hypogranulation of mast cells
name 3 things that are contained in mast cells
histamine serotonin heparin – all contribute to the inflammatory process
what are langerhan’s cells
fixed macrophages in the skin that are increased in number in cases of atopic dermaitis
true or false
skin affected by atopic dermatitis has a much thicker epidermis than healthy skin
true
what are corneocytes and how are they related to atopic dermatitis
dead keratinocytes in the stratum corneum (outermost layer of the skin)
these are in a very thick layer in atopic dermatitis
what is the relation between atopic dermatitis and genetics?
explain
genetics plays an important role in atopic dermatitis
85% concordance in identical twins
name 4 potential causes of atopic dermatitis
genetics
immune system dysfunction
environment
perhaps altered skin permeability
how can immune system dysfunction be a potential cause of atopic dermatitis?
the reaction itself is immunogenic (invokes immune system)
name 4 ways in which the “environment” can cause atopic dermatitis
chemicals
dry climates
stress
staphylococcus aureus
how can staphylococcus aureus cause atopic dermatitis?
when staph colonizes the skin, the barrier function of the skin is impaired. this colonization impairs the microbiome of the skin
we normally have commensal bacteria on skin to prevent overgrowth of more pathogenic organisms like staph aureus on skin.
is atopic dermatitis an autoimmune disease
yes
true or false
there seems to be a genetic relation in autoimmune disorders
true
true or false
staph aureus is not a pathogen
FALSE
it is - can alter and disturb cells in skin – can increase skin permeability
as mentioned, altered skin permeability can be a cause of atopic dermatitis. what are some causes of this?
what is the result of altered skin permeability?
could be genetic
could be due to dry climate
colonization of staph aureus
disturbance in fillagrin - disturbs connective tissue
type 4 hypersensitivity
entry of allergens – atopic dermatitis
true or false
the skin is virtually impermeable
TRUE
increased permeability due to factors above can lead to entry of allergens/antigens and result in atopic dermatitis
what is atopy?
genetic tendency to develop allergy conditions such as atopic dermatitis – exaggerated IgE response to harmless substances
___% of people with atopic dermatitis have mutations in gene for fillagrin
30%
overall, atopic dermatitis is usually associated with…
INCREASED SKIN PERMEABILITY
name the 1 specific gene in which mutations seem to correlate to atopic dermatitis
CARD11 gene
what does the CARD11 gene encode for?
the signaling pathway for the development and function of immune cells and lymphocytes
how is hygiene related to atopic dermatitis
exposure to some microorganisms, like parasitic infection with helmjinths, actually shows a protective role in preventing AD
true or false
children with poor hygiene are at LOWER RISK for developing AD
TRUE
exposure to some microorganisms has actually been shown to protect against AD
also, commensal bacteria on the skin protects from colonization of the skin by staph aureus
atopic dermatitis is driven by _______
hypersensitivity - specifically type 1 with a little bit of type 4
type ____ hypersensitivity is an anaphylactic reaction
type 1
explain the mechanism of type 1 hypersensitivity
IgE - humorl antibody - binds mast cells and they degranulate, releasing a variety of inflammatory mediators such as histamine, serotonin, and heparin – INFLAMMATORY REACTION
upon second exposure to antigen, histamine and other strong vasoactive substances are released
local release causes hives and skin flares, itchy, red skin, while a massive degranulation all over the body will cause systemic anaphylaxis
should children be introduced to common allergens earlier or later in life?
earlier
what is type 4 hypersensitivity called
cell mediated or delayed hypersensitivity reaction
explain how type 4 hypersensitivity is involved with atopic dermatitis
cells migrate to site of antigen
antigens enter and are trapped - lymphocytes pour in and attack the cells to which the antigen is attached
poison ivy is a common example of what type of hypersensitivity?
type 4
true or false
type 4 hypersensitivity involves antibodies
FALSE - type 1 does - IgE
type 4 involves cells that migrate to site of infection like T cells, NK cells, and macrophages
type 4 hypersensisity is regulated by 3 kinds of cells
what are they?
NK cells
T cells
macrophages
