Mast Cell Disorders Forum

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http://mastcelldisorders.wallack.us/yabb/YaBB.pl General Mast Cell Disorders Discussion >> General Mast Cell Disorder Discussion >> Before Bloodwork for MCAD - Stop all Antihistamines?? How many Days Prior? http://mastcelldisorders.wallack.us/yabb/YaBB.pl?num=1318520619 Message started by Futurehope on 10/13/11 at 04:43:39

Title: Before Bloodwork for MCAD - Stop all Antihistamines?? How many Days Prior?
Post by Futurehope on 10/13/11 at 04:43:39

Lisa, the moderator, was gracious enough to give me a list of tests to do to begin my diagnostic journey.

Am I supposed to stop all anti-histamines, both H1 and H2 blockers before the tests? If so, how many days am I supposed to be off of them?

Thank you so much for your help. I feel like there is hope, finally, in truly understanding my medical mystery.

Title: Re: Before Bloodwork for MCAD - Stop all Antihistamines?? How many Days Prior?
Post by texan1960 on 10/13/11 at 07:04:20

You don't have to stop your antihist for the "standard" beginning tests...I just got a blood draw for a bunch of the tests-tryptase, IG's, etc. I didn't have to stop any medications. If you were to have skin scratch test allergy testing they usually ask it, but not for these tests as far as I know. Hope this helps.

Title: Re: Before Bloodwork for MCAD - Stop all Antihistamines?? How many Days Prior?
Post by Futurehope on 10/13/11 at 10:47:24

Thanks. I just assumed (incorrectly), that if the anti-histamines, and leukotriene inhibitors, and H2 blockers helped, then the testing would not accurately reflect my condition if the meds were "counteracting" my misbehaving mast cells.

But, from what you are telling me, the by-products of misbehaving mast cells are still present, and one can do a blood test or a urine test even if there are medications counteracting the effects of the degranulating mast cells, right?

Title: Re: Before Bloodwork for MCAD - Stop all Antihistamines?? How many Days Prior?
Post by Lisa on 10/13/11 at 13:45:38

Hope, I understand your thoughts, I had the very same! You´ve got a point, the use of the antihistamines end up making you more stable and with that stability will give you less degranulation and therefore "influence" your results in supposedly not allowing the mediators to be found. This is indeed possible. HOWEVER....

We test our mediators in two ways, one is as a baseline the other in crisis. It´s important to try to get BOTH for by having both not only does the doctor gain an understanding as to your daily condition, but also as to the extent of your reacting.

Yet, it still doesn´t justify going off the meds.

By establishing a baseline, you see whether the degranulation is on a chronic basis or not. This is acutally MORE important than in crisis because when you have a reading of a baseline of chronicly high histamines or chronicly high tryptase, this means that the MCs are constantly putting these mediators out. It´s confirmation of Mast Cell activation. The tryptase does this as well and it has the added benefit (if you can say that) of telling the doctors what your MC burden is.

Now, this next statement is conjecture on my part. I´d love to know if this is really true, but I suspect I may be close.

Let´s say you´re on constant antihistamines and leukotrine blockers and your urine histamines return high as a baseline. Well, then your chronic degranulation is so high that there´s no questioning the presence of some kind of MC activation. You have a positive confirmation and indication of a mast cell disorder then.

But lets say you´re on antihistamines and the urine histamines return normal. The most likely even if you were NOT taking them, you tests would still probably come back within the normal ranges. I think that if this were my case, THEN would talk with my doctor asking that I stop taking my antihistamines in order to know what the true situation was. From what I understand, not taking the anithistamines will not affect the levels of histamine themselves within the urine, but what it does is take away the stability you had and this will then allow you to be more reactive and it would then allow for a bit more of mediators to be released. However, I rather think that this would still not be in great quantities.

Now, we here have heard that Dr. Castells will tell her patients to NEVER go off of their antihistamines. It´s often too dangerous for us to do so and doesn´t justify the risk we take. This makes sense, for if you are soooo unstable and go through so much anaphylaxis, it will make no sense to try to measure the mediators if you die in the process!!!! :o Therefore, she tells her patients to NOT STOP THEIR MEDICATIONS!!

Yet, this may not apply to every patient in that there are those who are leakers and they don´t have half the fun :o that the shockers have, so I think that each patient needs to SPEAK WITH THEIR DOCTORS in order to know what is best for them!

Lisa