Why am I itching???????

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Originally Posted by OakLeaf

Unless it's a food that you are still taking in. Have you done a challenge diet recently? Especially if you're continuing to develop new allergies, you may need to go onto a rotation diet. HUGE PITA, but totally worth it if your immune system is still developing new allergies. :(

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Ugh, that does sound like a huge PITA. No, not really, except that I did try laying off milk the past week (mostly giving up my daily lattes in favor of black coffee). No difference. I have noticed that I am having immediate reactions to skin contact with certain plants in the backyard. A few nights ago I picked green beans for dinner - within literally 5 minutes of coming in the house, my forearms, which had contact with the green bean leaves - broke out. Last night I went out to tend, very briefly, to the tomato plants - my legs had a slight outburst after that. However, I can't think of any gardening activities that I was doing when I first started itching 4 weeks ago.

Thanks for the Aquaphor tip ny biker. I hope that you are feeling better soon.

Tomato leaves are a common irritant, but if you're reacting to a lot of different kinds of leaves, it might not be the plants at all, but airborne molds that have settled on the leaves?

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Originally Posted by OakLeaf

Tomato leaves are a common irritant, but if you're reacting to a lot of different kinds of leaves, it might not be the plants at all, but airborne molds that have settled on the leaves?

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I don't know, but I certainly wish I did. I am hoping the dermatologist might have some ideas. I do know the pollen counts have been high.

My eczema went away completely when I stopped consuming gluten. (wheat, oats, barley, rye, spelt, triticale)

25 years of randomly flaring and subsiding miserable itching yuckiness, and that was all I had to do to make it go away!?!?!? Grrrrrrrr..... :mad: Wish someone would have told me in the 1970's....

NY Biker, I hope that yours gets solved quickly!

Thanks for checking in. I've been off the anithistamines since Wednesday, and am tapering the prednisone per the doctor's prescription. Appointment with the allergist/immunologist is on Tuesday -- I've started taking notes on all kinds of fun stuff to tell him about, in terms of previously identified allergies and prior outbreaks of unexplained red spots and rashes.

So, just got back from the allergist. The conclusion in summary: we don't really know what caused the reaction.

He thought the crab cakes sounded like the most likely cause, due to the timing of when I ate them and when the symptoms began. Then he tested me for allergies to a bunch of different foods but none yielded a positive result. However, he told me that the tests for food allergies are less reliable than tests for things like mold and dander, and in fact the test for cashews was also negative even though I've had a clear reaction to them in the past. Also it's possible that different types of crabs have slight differences in protein structure and one could cause an allergy while the other doesn't.

So he recommended that I avoid crab and other shellfish for now. In a few months, I can try a nibble of someone else's crab cake. If I have no reaction, I can try a larger nibble at another time, and if that's okay I can have a whole bite. If there's no reaction to that, I can have a whole crab cake and I'll probably be okay.

In the meantime, he prefers Zantac as an antihistimine for this type of reaction, and he recommends I keep some on hand (and I can keep the Claritin around also -- no harm to use both) in case I have problems in the future. He's not a big fan of Benedryl unless I'm having trouble sleeping due to the itch (which definitely was the case with this recent attack).

I was prepared for negative test results, so I'm not really disappointed or surprised. Overall I liked the doctor a lot. This was my first visit with him. He's an older man (called me "young lady" twice, which is something I rarely hear these days :D) but from talking to him I could tell he keeps on top of current research.

Some other interesting things he mentioned -- a large number of people who get hives have them due to an autoimmune response, not because of a specific allergy trigger. Food allergies are more likely to manifest within ~12 hours of eating the food, so he wasn't particularly interested in anything I'd had prior to the day the attack happened (the symptoms began around 7 pm). It's possible that the symptoms might return in a few days, because I'm still tapering off the prednisone and just as there is a 1-2 day lag for that drug to take effect, there is a 1-2 day lag for it to completely clear your body. So I should have Zantac handy for the next week or two, just in case.

I do love crab cakes and will miss eating them.

BTW I did not mention the possibility of pseudoallergy/histamine intolerance to the doctor, mostly because there were so many other things to discuss while I was there and I would like to focus on the crab thing for now. But I'm keeping it in the back of my mind for the future. For example in the week before this happened I changed two bike tires (latex exposure) and ate a tuna sandwich with avocado which has the same allergen in it as latex. In the future I'll try to be aware of those kinds of multiple exposures that might cause a cumulative affect. I did have the same sandwich with avocado yesterday for lunch, and have not had any ill effects.

I have to say, allergies suck, but on another level they are kind of fascinating.

Hi NY Biker,

I've had hives pop up for no reason at various times throughout the year. After undergoing allergy testing and coming up negative, the drs. were unable to give me a reason for the condition. We explored the stress issue and that wasn't relevant. In any case, I carry (or carried) Loratdine around with me and would take one whenever I felt the itching sensation, that took care of the symptoms.

I've had reaction to shellfish, but only if I ride on the day I eat it. Otherwise, I don't react. Look up "exercise-induced anaphylaxis" if you rode that day.

Interesting. I've always thought of Zantac as an ulcer medication (a proton pump inhibitor? my brain is rusty), rather than an antihistamine.

I may have to give that a try the next time I have a mysterious reaction to something.

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Originally Posted by NbyNW

Interesting. I've always thought of Zantac as an ulcer medication (a proton pump inhibitor? my brain is rusty), rather than an antihistamine.

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It is a heartburn/ulcer med but it is an H2 antihistamine, not a PPI. Things like Benadryl and Claritin are H1 antihistamines. I think the use of the H2 blockers for allergies is a somewhat new use (not an approved indication that I know of, but I'll look and see.) From what I read it looks like it is usually only recommended when the allergic reaction is hives. Again, just a quick look at this point. I'm a Dr of Pharmacology and someone who, as my mother always said came out of the womb with allergies, and yet I hadn't heard of docs using ranitidine for allergies. :)

Thanks, Possegal!

Can you explain the difference between H1 and H2 antihistamines to a layperson? I have not heard those terms before.

I have a great zucchini cake recipe replacer if you're Jonesing for some crab cakes. ;)

I had hives last winter, at the end of the "wool" season; they appeared mysteriously after a few years of no problems with merino. I've had a history of hives, weird allergies, asthma, so while not unusual, the fact that the wool started to bother me all of a sudden, was weird. Someone here on TE suggested the Zantac, combined with Claritin, and it worked right away.
NY Biker, I feel for you. I have gone through several bouts of what you had and it's scary and annoying.

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Originally Posted by NbyNW

Thanks, Possegal!

Can you explain the difference between H1 and H2 antihistamines to a layperson? I have not heard those terms before.

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I can try. :) I taught that topic YEARS ago in a pharmacology class but let's see what I remember. 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. Such as = you have H2 receptors in your GI and when histamine binds to them, gastric acid secretion increases. So if you block that with an H2 antihistamine like Zantac, less gastric acid, less heartburn. THe H1 receptors are what is involved in allergic reactions. THey exist on a lot of different cells including in your airways, where if stimulated by histamine the bronchioles will constrict. Though I think you also have H2 receptors in the airways that if stimulated dilate the bronchioles. So an H2 blocker is not what you would want if you were having a respiratory reaction allergic response. There are a lot more H1 effects like vasodilation (which would be involved in the edema that you can see with allergies), but I'd have to go look them up. :)

I'll have to dig a bit more to see how blocking H2 treats hives though. It was quite interesting to see that and now I'm curious. I'm sure much more is known about histamine and its receptors since I had any professional reason to be paying close attention. :)

Hey, that's a very helpful explanation! Enough to know what to pay attention to in case of a flare-up.

And good to know that Zantac is possibly helpful in these situations, since I've usually reached for the Benadryl. Nice to have some relief without getting knocked out.

ny biker, hope your symptoms continue to calm down!

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Originally Posted by Possegal

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.

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

(click for bigger)
http://www.ajcn.org/content/vol85/is...0744060001.gif

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).

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.

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Originally Posted by 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?

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Oops, sowwy! :p

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

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

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Originally Posted by 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.

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True enough! :)

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Originally Posted by Possegal

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

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

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. :)

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!

You know, that chart made a lot of sense to me, even as someone with no scientific background. Almost every weird symptom I have had in my adult life was on there... after my debacle three years ago, with no real resolution (yea tell me I have fibromyalgia because there's nothing else to say), I realized after looking at the chart, that I do know I have allergies and asthma. And all the stomach issues, skin issues, rashes, hives, palpitations, blah, blah, blah are caused either by stress, which induces a histamine response, or some some environmental trigger that switches from year to year. If I treat the allergies and keep the stress down, I am healthy.
When I was around 34-35, I started having the palpitations, followed by a long bout of asthma and hives. I went from specialist to specialist, with little resolution. When the stress went away (I quit teaching aerobics 7 days a week, moved across the country, and got away from the dust in AZ) most of it went away for years. I know that a certain level of exercise, which is basically over training for me also induces these symptoms, even without any asthma showing up.

Thanks!

Sigh. It's back again. Same symptoms as in July. Woke up itching last night, was better during the day today and then got worse again. I'm hoping it won't be as severe as it was in July, especially since I started taking the antihistamines right away. Also hoping I won't need the prednisone this time, since I just don't want the side effects.

I haven't had any sea food lately except for tuna salad early last week. The only new/rare food I've had in the past few days was Newman's Own pizza with pepperoni. Of course now I'm thinking maybe food is not really the cause.

Oh crap - so sorry to hear this! Hope it will be very short-lived this time around, and that you can finally get to the bottom of it. Must be very frustrating! :(

I just had an appointment with my allergist today to discuss this. He's also thinking that food is not the cause. I'm going for a blood test -- thyroglobulin antibodies and thyroid peroxidase antibodies, if I'm reading his handwriting correctly. The test may show that I've developed antibodies to my thyroid, which apparently is a problem for some people. Or, it might show that we can rule that out, in which case...?

Also I'm going to get some Zirtec, to see if that works better than the Claritin that I've been taking so far.

The good news is that the last attack was not as bad as the one in July. I don't know if that's because I started taking all the antihistimines sooner, or I was just lucky.

whispers quietly... (do I dare to point out that people with undiagnosed celiac disease will often produce antibodies to their thyroids? and have skin reactions? and edema?)

{I only know much about one disease, but I will promote awareness of it every time I see something that might be related... cuz the darn thing is so rarely diagnosed until very late in life}

Oooh, doesn't that mean big dietary restrictions? I was bummed enough thinking I could never have crab cakes again. Oh well, we'll see what the tests say.

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Originally Posted by KnottedYet

cuz the darn thing is so rarely diagnosed until very late in life

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...and lately they're finding that it may not even have onset until late in life.

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Originally Posted by OakLeaf

...and lately they're finding that it may not even have onset until late in life.

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That's the story in my family. Everyone in the family knows that sometime around middle age you have to stop eating wheat.