Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
20 Cards in this Set
- Front
- Back
|
poison sumac
|
eastern us and near the water. (for my own info)
|
|
|
Hallmark of acute contact dermatitis
|
free floating epithelial cells (spongiosus)
|
|
|
streakiness
|
a clue of contact dermatitis
|
|
|
what is the main blistering disease
|
contact dermatitis
|
|
|
people that have disturbances in the epidermal barrier...
|
have more chance of getting contact dermatitis.
|
|
|
Antigens
|
haptens - low MW, lipid soluble, chemical reactivity.
|
|
|
sensitization
|
two phases - afferent and efferent.
|
|
|
Pathogenesis - first phase
|
Langerhans cell in epidermis finds and antigen and migrates to paracortical region of LN (due to keratinocytes releasing tnf-alpha and telling them to go there). THen it presents (with secondary signals char by stabilization, presentation, costimulation) to T cells and CLA positivity develops and memory T cells form.
|
|
|
Pathogenesis - second phase
|
Keratinocytes recog damage and make ICAMs (via TNF-alpha) so lymphocytes can get in through BVs
Langerhans present to these memory T cells that have the right specificity and then inflammation occurs. |
|
|
Streaking
|
streaks of inflamm bc the keratinocytes are localized when they upreg icam. obviously keratinocytes don't move. that's why the response is localized.
|
|
|
the body responds to the area of greatest antigen [] and then moves down the gradient.
|
THEREFORE YOU CAN'T SPREAD IT BY SCRATCHING!!!
|
|
|
Stopping the response
|
T regs and keratinocytes (mainly keratinocytes) stops the response.
Keratinocytes bind the antigen but can't provide costimulation so it just holds and mops up the antigen. |
|
|
Intensity of rxn depends on...
|
bodys immune rxn and
[] and duration of the antigen exposure. |
|
|
"id" reaction
|
when keratinocytes fail to suppress the rxn so it spreads.
|
|
|
Baboon butt syndrome
|
a systemic contact dermatitis
allergy already there to a topcial antigen then you consume something orally that cross-reacts and you get a response in very specific sites (axilla, buttocks, etc.) classically poison ivy and cashews or mangoes. |
|
|
the issue with patch testing
|
anyone can do it, but it is hard to interpret it.
|
|
|
Chronic irritant reaction
|
a chronic one is water!!!
|
|
|
note abt this...
|
read the lec notes first.
|
|
|
irritant dermatitis
|
not immunologic. happens to anyone.
|
|
|
Clue to irritant and not allergic contact dermatitis
|
less itching and more burning.
|
