Why am I itching???????

[Dianyla]

Histamine can bind to a number of different histamine receptors - H1 and H2 are the prominent ones that the drugs tend to target, but there are H3 and H4 receptors as well. Heck, they may have found some others by now. What the histamine causes to happen, depends on what receptor it binds to. And the receptors are more prominent on different tissues.

Here's a neat map of histamine pathways in the body:

(click for bigger)

[OakLeaf]

Ack, that chart made my head explode!

I was a little surprised that edema (especially facial edema, one of my main symptoms) wasn't on there. Is that related to leukotriene rather than histamine?


ETA: I was really glad to see tachycardia and arrhythmias on that chart! My allergist is well aware of tachycardia in the sense of an increased heart rate that stays within an essentially normal range (although most doctors will roll up their eyes at that one), but I've NEVER had anyone believe that my SVTs correlate with my food allergies. I've been 100% sure of that one for a couple of decades now.

NYB, glad you're feeling better, and hope that avoiding crab takes care of it in the future (although I agree, it would suck if I couldn't eat crab).

[Possegal]

Well since I'm not teaching pharmacology or pathophysiology here, I was aiming to not explode any heads. Then we'd have to put that on the chart too.

I'd put edema in that chart - it is a histamine reaction. As is true of dang near everything in the body, it is probably a combination of things, but in experimental studies you can induce an edematous reaction by infusing histamine.

[Dianyla]

Ack, that chart made my head explode!

I was a little surprised that edema (especially facial edema, one of my main symptoms) wasn't on there. Is that related to leukotriene rather than histamine?

Oops, sowwy!

Edema is actually covered on the chart under endothelial permeability, but that isn't very obvious if you haven't taken biology/anatomy.

[Possegal]

Except that the chart actually shows other clinical signs of histamine's response, so the lack of listing edema, along with flush and uticaria and things like that, is in my opinion, an error. Otherwise you could say that "flush" is already covered under vasodilation. Busy chart for sure, though I've got a way busier one hanging on my door. So I think edema should have been on there.

Similar to this, but the one in poster size has a lot more going on, just can't find a link to one similar. http://www.nature.com/nrn/journal/v4...nrn1197-f3.jpg

[Dianyla]

Except that the chart actually shows other clinical signs of histamine's response, so the lack of listing edema, along with flush and uticaria and things like that, is in my opinion, an error. Otherwise you could say that "flush" is already covered under vasodilation. Busy chart for sure, though I've got a way busier one hanging on my door. So I think edema should have been on there.

True enough!

Similar to this, but the one in poster size has a lot more going on, just can't find a link to one similar. http://www.nature.com/nrn/journal/v4...nrn1197-f3.jpg

Ooh, need to go play with google image search again...

[Possegal]

the kinases and all their downstream effects can make for a very busy poster. I've spent a lot of time last few years dealing with some kinase inhibitors and I stare at those pathways and my head explodes.

[Norse]

I finally saw the dermatologist yesterday. He actually thinks that high stress levels may have triggered it but, because I do not have a noticeable rash anywhere (just bumps and itching) he wants to make sure it's nothing systemic. So... in about another 3 weeks I have an appt with the primary care doc for a physical including blood work and urinalysis. Meanwhile, dermo told me 1 benedryl before bed and Sarna lotion. I had been doing the Benedryl on and off but trying to stay off as, not only does it knock me out at night, it keeps me sleepy the next morning. It does help though. Picked up some Sarna lotion for sensitive skin yesterday and ohhhhhhhhhhhh what a relief this lotion has been!