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  #1  
Old 02-18-2012
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Question NBME 2 confusing Concept; Allergic Rash

A boy who went into the woods for hiking came back with rashes over his hands. Which of the following is involved in his illness?

A. Antibody, Complement C5-9
B. Circulating Immune complexes, C5a, neutrophils
C. Cytotoxic T lymphocytes
D. IgE, Mast cells, Histamine, Cytokines
E. Lymphocytes, Macrophages, Cytokines

Guys pls post the answer with explanation

Thanks
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  #2  
Old 02-18-2012
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Default D

Seems to be an allergic reaction. Immunologically speaking - a Type I hypersensitivity reaction involving IgE, mast cells etc. (You know the drill).
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Old 02-18-2012
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I am not sure but I think its type 4 HSRxn, contact dermatitis.
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  #4  
Old 02-18-2012
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Apologies, You're probably right.
http://en.wikipedia.org/wiki/Toxicodendron_radicans

In that case, it would be "C".
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  #5  
Old 02-19-2012
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Ans....C.....its Type IV Hsy REACTION.....its more like a contact dermatitis...linear vesicles means the thorns or plants drags when he was hiking.
so CTL's Th1 cells and macrophages involved...the answer would be C
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  #6  
Old 02-19-2012
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Quote:
Originally Posted by doctordexter View Post
Ans....C.....its Type IV Hsy REACTION.....its more like a contact dermatitis...linear vesicles means the thorns or plants drags when he was hiking.
so CTL's Th1 cells and macrophages involved...the answer would be C
Then why not E.
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Old 02-19-2012
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Quote:
Originally Posted by patho2012 View Post
I am not sure but I think its type 4 HSRxn, contact dermatitis.
Then whats the answer E or C
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  #8  
Old 02-19-2012
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I think E because T-helper Naive went with the IL-12 pathway to become Th-1 in Contact Derm TYPE IV HSN. Th-1 later produces IFN-gamma marcophage supercharger induction of giant cells

T-cell mediated cytotoxic is part of cell-mediated immunity Just like Type IV hypersensitivity. I think T-cytotoxic is involved in transplant rejections.

Whenever i see questions like this, they are always about the plants. so it is Contact derm.
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  #9  
Old 02-19-2012
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Quote:
Originally Posted by jinni View Post
Then why not E.
the answer is E.
Macrophages and cytotoxic T cells always go together, mediating the cell-delayed hypersensitivity
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  #10  
Old 02-19-2012
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Now all you guys read Qid 1133 in UW.
What do you guys think now........
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  #11  
Old 02-19-2012
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Default sorry guys, just to repost

the answer is E b/c I don't think cytotoxic T cells alone is sufficient.
Macrophages and cytotoxic T cells always go together, mediating the cell-delayed hypersensitivity

I am just confused whether it is contact urticaria ( type 1) or contact dermatitis (type 4), who knows what is there in the forest??? Anyone can help???

Also, contact urticaria appear within 30 min after exposure, contact dermatitis appears within days after exposure...
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Old 02-19-2012
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Quote:
Originally Posted by jinni View Post
Now all you guys read Qid 1133 in UW.
What do you guys think now........

Well the question in UW is much clearer, at least they ask what cell directly causes the skin lesion, with the description of it. The allergic rash is called urticaria, which is mostly macula. The contact dermatitis rash is mostly papular and vesicular. (roughly)

In the NMBE question, since E is better than C and Langerhans cells are macrophages in the dermis, why wouldn't E seem right?

@jinni, do you have the correct ans?
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  #13  
Old 02-19-2012
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So i think its E now.
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  #14  
Old 02-21-2012
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Is that the whole question?
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Old 03-05-2012
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cytotoxic is TYPE 2 HS...so incorrect

this is classic TY.4 HS - Cell-mediated delayed HS = the correct ANS = E
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  #16  
Old 03-05-2012
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Quote:
Originally Posted by dr.dhruvdesai View Post
cytotoxic is TYPE 2 HS...so incorrect

this is classic TY.4 HS - Cell-mediated delayed HS = the correct ANS = E
I agree man!
That sounds like poison ivy, which is a Type 4 HSR . CD4, Th1 cells Cytokines.
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  #17  
Old 03-05-2012
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Delayed hypersensitivity dont develop that FAST??????????????? usually takes days to develop so that rules it out.
i would go for type 1 hsn
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  #18  
Old 03-05-2012
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Idea!

mr.angel.... u r rite

and

delayed requires time after 1st exposure...

but once exposed .....

Nxt time they develop this fast ...n thats a fact .UW says so.
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the question didnt mention any prior exposure so i would go for Type 1 = D
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  #20  
Old 03-05-2012
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Actually, the one that needs prior exposure is Type I HSR. So still E is the correct answer. Plus, the vignette clearly wants you to know about poison ivy, tell me what plant causes type 1 HSR in the hands? But still you might be correct. This is a good question.

Last edited by LatinGeorge; 03-05-2012 at 04:16 PM.
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  #21  
Old 03-05-2012
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anybody the official answer
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  #22  
Old 03-05-2012
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Its contact dermatitis type IV.

If it had been type I it would have caused vasodilation causing hyperemia and smooth muscle spasm causing bronchoconstriction.
he would nt be able to come back from forest even LOL

its type IV only mild rash
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  #23  
Old 03-05-2012
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so all type 1 have bronchoconstriction and die? heheheh i guess its nr IV then
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Old 03-05-2012
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lol no i dnt get why medical students get a statement and apply it all over medicine if u know there are handful of laws in medicine (mendels laws) and tons of theories
So only laws can b applied universally
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Embarrassed

i guess that it's type I because, even after sensitization, with typeIV it my take 48h untill the rash appears..
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  #26  
Old 03-06-2012
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Default what is the answer?

I read all the posts but nothing seems clear. I thought it was D.
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  #27  
Old 03-06-2012
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Warning!

the question must be incomplete... he must not have written the entire question.... and we here are contemplating why how and whaT !!
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