Immune system accelerates PD

As this article made me think to an allergic reaction I started searching for allergies and found this old article saying that allergic rhinitis increases your odds for getting PD by a factor of 3:

I did some research about anti-allergy pills and apparently these pills are called antihistamine pills. So I looked whether antihistamine pills might have beneficial effect on people with PD, and I found the following article:

This article discusses a particular antihistamine drug that makes it possible to remove alpha-synuclein. However, maybe other antihistamines drugs could help to surpress the immune system attacking the brain. So I have a question for the research team:

To what extent have anti-allergy medicines been investigated for PD ?
I found an article claiming post mortem analysis of people with PD showed increased histamine levels in the brain:
Hi MisterX

To my knowledge, no clinical trials testing antihistamine drugs in people with Parkinson's have yet been carried out.

The article you found on our website last year ( suggests there may be some potential for antihistamines in Parkinson's, but I don't think there are any trials planned yet. Obviously if we do hear of any we'll highlight them on the website and in our magazines.

However, there is a growing body of research evidence to suggest that inflammation in the brain may play a key role in nerve cell death in Parkinson's - and that drugs that can reduce this inflammation could have protective effects.

We're funding research in this area to help us better understand the inflammatory processes that occur inside the brain in Parkinson's:

And to develop potential treatments that combat inflammation:

I hope this helps to answer your questions.

Best wishes


(research team)
I also have a similar question for the research team: are you involved in or aware of any studies that looked at the impact of cortisol and/or transcortin on PD?

Reason I ask is that I understand that one of cortisol's key functions is to control the anti-inflammatory pathways in our body and I have both PD and low unbound cortisol (because I have too high transcortin). Given the likely role of inflammation in PD I wonder (a) if there is a link that has been studied and (b) if there are any ideas out there on what could be done about it?

Warm regards,

I have always been an "itchy" person, but I found that when I developed PD 2 or 3 years ago this tendency was amplified. I asked the GP about it, and he put me on Cetirizine Hydrochloride 10mg. I take one every 3 days, and that pretty much takes care of it. No-one has ever said to me that there might be a link between alergy type reactions and PD - I would be fascinated to know.

I know from the Forum that I am not alone with this itchy skin thing. Can anyone else throw more light on this?
Hi all,

I've been taking antihistamine (ceterazine hydrochloride 10mg) for about 11 years for a condition called Urticaria - possibly physical Urticaria as it reacts to the cold (I get all itchy around hair-lines, hands & feet, slightly swollen hands & face goes red & hot) symptoms last for around 10 minutes. I saw an article in a past Parkinsons magazine for a antihistamine called latrepidine that I cut out to take to my doctor & ask him if it's worth me swapping to this drug, but haven't found a medical reason to visit him yet!
I'm wondering now if instead this drug helping PD, maybe research
should be looking at what causes us to release histamine from cells in the skin in the first place & if this has anything to do with the excess of alpha-synuclein? Just a thought!

Thank you Drobb. Latrepirdine has been used for Alzheimers, particularly in Russia, and has been trialed in the US. It apparently may have some potential as a neuroprotector, and be of value in the treatment of PD. Can it be prescribed as a bog standard anti-hystamine by a GP? This may be a way of stealing a march on Big Pharma. Can Research throw any more light on this?
Hi again everyone

I've done a bit of investigating and it doesn't look like Latrepirdine is widely available as an antihistamine medication so it's probably not something that a GP could prescribe at this stage.

As far as I know, so far there have not been any clinical trials testing antihistamines in people with Parkinson's - so it's too soon to know if taking any type of antihistamine is beneficial.

I'm afraid I haven't been able to find much research into the relationship between cortisol levels and Parkinson's. I did find this one interesting study which suggests that taking the Parkinson's drug levodopa reduces cortisol levels in the blood:

Best wishes

Research team
Claire, thanks for all your replies.

Drobb, you have been taking antihistamines ? Do you have PD also ? Did your doctor notice you to have a slow progression of PD ?
Hi Claire,

Thanks too from my side for your responses. Funy you mention that study. I also came across it just a few days ago and find it quite crucial because if there is any truth in the hypothesis that low cortisol is behind PD (via inflammation or other mechanisms), then that study really just means that when we take L-dopa we are just making things progressively worse (while alleviating short-term PD symptoms). Actually, this hypothesis seems highly consistent with everything else I know about PD, L-dopa, and Cortisol and just makes me believe that actively managing cortisol might be very important for managing PD. This is where I'm stuck at this moment, as I have no clear idea on how to best manage my cortisol levels? Do you happen to have any ideas of how to go about this?

Pls take a look at my recent post on this exact subject where I refer to the same paper you mention and describe in a bit more detail the different ways I currently understand there are to manage cortisol (and none is really great - though licorice seems so far the one with the least downsides to me):

Any further thoughts/advice you may have on this subject would be greatly appreciated, of course!


Hi Mister X,

Yes I have been dx with pd just over two years ago & had symptoms for almost a year before that & can track back 6 yrs previous to frozen shoulder type problems so probably could say i'm 8yrs in so to speak? The point is I've taken antihistamines longer than having pd and wonder if what ever caused me to need antihistamines in the first place is the same thing that has developed and led to PD? As for my progression of PD, i'm 2yrs in and only taking 1 Azilect tablet and one Requip XL 2mg tablet daily. I last saw my pd nurse pre xmas and was advised to up dose to 4mg daily but although I can say I now notice i'm loosing function more & more in my affected side i still haven't started the recommended dose as i still feel i can manage ok for now!
I've added a link to Urticaria & think i have physical/cold urticaria as you may be interested in the possible causes & may spot a link somewhere? also there is a section that refers to a range of antihistamines. This may or may not be helpful!(there are lots of websites offering slightly different information)

Feel free to ask anything else!


I latched on Ifs mention of Liquorice in his last post on this topic.
I like liquorice and have self - prescribed it, but for the alleviation of constipation ! could it be double actinc against PD?
Hi CW,

I guess I'm just stating the obvious by saying that I believe there's a good chance it may indeed. As you seem to have some experience in taking licorice, would you mind sharing how you go about it and if you feel is impacting your PD in any way. More specifically:
1. How much licorice do you take; in what form; how frequently; and for how long?
2. At what phase of PD are you on (how long since DX? already taking l-dopa meds like Sinamet; how long after DX did you start with l-dopa) and when did you start with licorice?
4. Do you notice any positive/negative impacts for PD when you take it? (any impact on trembling/rigidity? more energy? less craving for sugars? do you feel PD is evolving any faster/slower/the same)?

Warm regards,