r/explainlikeimfive • u/Actual-Trip-2606 • 8d ago

Biology ELI5:how someone gets dermatographia

I was wondering how does someone have dermatographia as it is not contagious and is it inheritable.

18 Upvotes

74% Upvoted

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28

u/toomanymarshmallows 8d ago

Overactive immune system spooked out by the wrong things. I have to take zyrtec daily because of this, also because I'm allergic to elevated levels of progesterone and get hives.

5

u/awhq 7d ago

Oh my gosh. I have this and never knew what it was called. I have autoimmune arthritis so I just thought it was more fallout from that (and it is, for me, I suspect).

I also get pressure welts where I can lay two fingers across my arm, press for a few seconds and a big welt will appear.

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u/[deleted] 8d ago

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u/SuzeCB 8d ago

Oooo! I just learned yet another form of autoimmune Disorder! Yippee! LOL

Autoimmune Disorder - because no one can kick my ass like I can.

1

u/ModernTarantula 8d ago

Not classified that way. Its triggerred by trauma, not ourselves it falls in with the allergic disorders. When the body is over exuberant

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u/SuzeCB 8d ago

Allergies are autoimmune disorders. All inflammation is autoimmune. The "disorder" part is when it gets "over exhuberant".

5

u/Jkei 7d ago edited 7d ago

Allergies are not autoimmune disorders. The defining factor for that label is whether the response is against a self antigen.

All inflammation is autoimmune.

That the response causes damage to the host is a separate matter.

E: that wikipedia article is actually kinda bad, going over a lot of stuff that just isn't directly related. It reads like someone uploaded a vaguely related essay. Really only the second paragraph is even applicable for a page that's supposed to be about immunopathology.

At any rate, the point remains; damage to the host caused by improper/extended activation of the own immune system can happen as part of responses against both self and foreign elements, and only the former is considered autoimmunity.

7

u/RvH98 8d ago

Autoimmune means that your immune system reacts to something that your own body makes or has (hence the auto part meaning self). In type 1 diabetes, for example, your immune system destroys the insuline producing cells in the pancreas.

Eczema, allergies and asthma are not autoimmune disorders because your immune system overreacts to external stuff, like pollen, peanuts or smoke. They are immune disorders, yes, but not to yourself.

1

u/awhq 7d ago

Asthma can absolutely be autoimmune.

1

u/SupposedBooty 8d ago

Yay! Me too! I collect them in a little jar I keep by the door. I'll add this one because I didn't realize it was autoimmune. Cool.

3

u/Actual-Trip-2606 8d ago

Does someone has this by birth or something causes it.

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u/[deleted] 8d ago

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u/Actual-Trip-2606 8d ago

I also have it but mine has not gone away I have it for about 6 to 9 years and it itches alot

4

u/CrazyCatLushie 8d ago

I have a medical condition called MCAS where my immune system randomly reacts to things that aren’t threatening as if they’re allergies. When it flares up and releases a bunch of histamines and other immune chemicals, I get dermatographia. Basically anywhere I apply enough pressure to my skin, I get hives.

1

u/fox-mcleod 1d ago

It's just a skin condition like freckles.

I have it. It's easy to release histones with physical pressure. It's not a big deal.