Derm

Discussion in 'Step I' started by Nematode, Jun 9, 2009.

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  1. Nematode

    Nematode

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    Jun 9, 2009
    Some of this derm stuff is quite annoying (specifically the vocab). Im guessing on the real deal they describe the word rather then say the word, like describe what acantholysis is, any pointers?
     
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  3. TMP-SMX

    TMP-SMX Senior Member Moderator Emeritus 7+ Year Member

    3,470
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    Jun 12, 2006
    MDApps:
    Acanthosis is thickening of the epidermis through hyperplasia. Acantholysis is breaking of the intercellular bridges (desmosomes) and the formation of bullae. Remember that acanthosis nigricans is darkening of thickened skin due to insulin resistance and often malignant adenocarcinoma of the GI tract.
     
  4. Nematode

    Nematode

    26
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    Jun 9, 2009
    any other vocab/hints for some of the other skin disorders?
     
  5. TMP-SMX

    TMP-SMX Senior Member Moderator Emeritus 7+ Year Member

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    Jun 12, 2006
    MDApps:
    Well you should definitely know how to describe each rash and what they mean by whether or not they are raised or not, their size, and their characteristics. Blanching vs. non-blanching. What it means if the skin is removed after finger pressure (Nikolsky's sign). Petechiae and platelets.
     
  6. quietude

    quietude 2+ Year Member

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    Feb 12, 2009
    I could never tell the difference between pemphigus vulgaris and bullous pemphigoid, even after re-reading FA.

    Here's the easiest way to tell them apart (assuming you're not given IF results): pemphigus vulgaris affects the oral mucosa. Bullous pemphigus does not.

    They always give you that if they don't give you the IF, and remembering acantholysis and Nikolsky's sign becomes secondary.
     
  7. scube

    scube 2+ Year Member

    bullous pemphigoid.(bp) is an autoimmune destruction of hemidesmisomes on the basement membrane. it doesn't affect the connections between cells so fluid gets under the sheet of cells and lifts them up creating bullae. also there is no nickolski sign bc the cells stick together.

    pemphigus vulgaris. pv. is a destruction of the desmisomes. the cells are no longer attached to one another and can be pulled off by finger pressure, positive nickolski sign.

    so nickolski sign happens when you destroy the biggest connection (which is vulgar,pv) the desmisome versus the hemidesmisome(half of a desmisome). in bp you actually get bullae like the name indicates. I like to think "I would rather stick together(bp) than be alone in the basement(individual cells on basement membrane in pv)

    I hope this helps.
     
  8. NCF145

    NCF145 Not Politically Correct 7+ Year Member

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    Oct 13, 2005
    The Beach
    Pemphigus vulgaris - Autoimmune disorder with IgG directed at the desmosomes. This results in acantholysis (of the stratum spinosum layer I believe) and a positive Nikolsky sign.

    Bullous pemphigoid - Has IgG directed against the hemidesmosomes. This results in separation of the dermis from the epidermis (as compared to an intraepidermal separation in p. vulgaris). Since the separation occurs below the epidermis there is no Nikolsky sign.
     
    Last edited: Jun 11, 2009
  9. scube

    scube 2+ Year Member

    I disagree with your def of nikolsky sign. it is bleeding/ sloughing of cells on finger pressure. i do think just from a pathophys point of view that pressing on a bullae in BP will spread the bullous because it will separate more cells from the basement membrane.
     
    Last edited: Jun 11, 2009
  10. NCF145

    NCF145 Not Politically Correct 7+ Year Member

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    You are right, the bullous doesn't spread. It creates one with pressure.
     

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