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Bizarre Escalating Head Shaking - Thoughts? [UPDATE - he's retired]

Long time lurker first time poster here looking for some ideas.

I have an odd case with my current horse and while I’m working very closely with my vet, I wanted to see if anyone had any creative ideas or out there anecdotes that might be worth pursuing.

I bought my 8yo TB in September last year. I went to see him and rode him myself. I also did a basic PPE with some radiographs (front feet & hocks) which he passed with flying colors.

The only concern was that this horse was VERY underweight, so as soon as I purchased him I dewormed him, did his teeth, and started to feed him more groceries. My vet watched his progress closely and he very quickly gained weight and better body condition. I was riding him lightly during this time (WTC) working on him using his body correctly and traveling forward and straight. I was also doing some stretches and core strengthening exercises with him from the ground as he was very stiff all over and kind of oddly muscled (pencil neck, REALLY defined glutes).

Body condition, stiffness, and overall symmetry improved. My vet was out every 4 weeks to reassess him, do chiro work, and was VERY happy with his weight gain and overall progress.

The one thing that started getting worse was his breathing and head shaking. When I tried him he did not head shake, cough, or blow at all. His previous owners swear he didn’t do this at all with them and they have plenty of videos of him going normally. After 1-2 weeks with me, I noticed he would cough/blow 2-5 times once we stepped into trot. Then it became more like 10 times. Then he would do some mild head flipping before he finished clearing. This is September - October and I personally have horrible fall allergies, so we opted to wait and see if this resolved itself.

November rolls around and it’s getting worse, so my vet had me try him on antihistamines (slowly ramping up the dosage). The first week he was coughing in his stall (new) but after that was only coughing/blowing under saddle, and the head shaking was getting progressively worse with less coughing/blowing, even as we upped the dosage.

During this time I am also doing other little trials with him - I had him on magnesium & Smartbreathe for 8 weeks with no change. I was adjusting his tack - different bits, different material bits, having the bit sit higher/lower in his mouth, Tight noseband, loose noseband. Anatomical bridle, normal bridle. Nose net. NOTHING made him improve (not even the nose net), but two things made him worse: he went NUTS when I tried to ride him in a (not too tight) flash noseband, which is interesting because when I tried him he was in a flash noseband and totally fine. He also panicked in a hackamore - walking backwards til I dismounted.

January rolls around and he’s unrideable. He starts flipping his head around as soon as I get on him. In trot, he’s shaking his head so violently he’s actually tripping up front. So I stop riding him and start trying to lunge him in both a bridle and halter. As soon as he picks up the trot the head shaking and flipping happens on the lunge too. If I turn him loose in my indoor, he will run around but will eventually start head flipping and coughing/snorting. It’s been two weeks since I’ve done anything with him for these reasons.

I had my vet out earlier this week and while he’s a bit stumped he’s taking it seriously. When I lunged my horse for the vet he decided to go straight up in the air, strike out, and tangle himself in the lunge line. A very extreme response to being asked to trot on a circle for 30 seconds.

The vet looked him over, checked in his mouth, and we x-rayed his head with no answers - all teeth look healthy, no fractures, no mucus build-up. I’m now waiting on (basic) bloodwork and will be scoping his throat sometime next week. If that yields nothing my vet suggested a dynamic scope to see what’s happening inside during work.

Any ideas or thoughts on where else to look?

For my horse’s basic setup if helpful - I’m in the northeast USA and he’s stalled overnight, turned out with a buddy in a good sized flat field with run in from sunrise to sunset. He has hay and water 24/7 and gets grain (TCS) 2x a day. Eats and drinks completely normally, pees and poops completely normally. Bright eyed and playful with his turnout buddy. Does not act sour in any way save for the head shaking - no girthiness or evasiveness tacking up/mounting. Not even tail swishing. He is a bit mouthy but beyond that he’s a really solid citizen to handle. The rear on the lunge line was completely out of character for him.

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Have you tried him on gabapentin?

It sound like there’s damage or irritation to the trigeminal nerve and it’s causing him pain. Has he had any injuries to his head since you’ve had him? How did the dental go?

Nerve pain can be VERY acutely and suddenly painful. I’d continue to leave him alone until you’re able to make headway on relief for him. If your current vet hasn’t mentioned the trigeminal nerve, I’d look around for someone with more experience in this, perhaps a larger referral hospital.


Trigeminal nerve pain?
C6/7 impingement?

The last 2 often start showing up when horses are fully mature and put into more work

What do his feet look like?


My vet was recently telling me about tiny spider or mite colonies associated with head shaking behavior he used to see when he practiced in west Texas/Arizona, and he had also had a local case here. I didn’t listen all that carefully to know the specifics, but the pests are evidently way deep inside the ear, tiny, and not readily visible. Just another thing to add to the possibilities.

I do recall his saying that treatment involved pouring liquid something inside the ear, and that you’d better pick the correct ear, because the horse would not give you a shot at doing the same to the other ear.


Oh my goodness!

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I can promise my horse is on vacation until this gets resolved, unless my vet instructs otherwise.

The spider thing is… horrifying, but I was planning to ask my vet to really check deep in my horse’s ears when he’s sedated for the scope next week.

And while my horse has had no head injuries that I know of, a gabapentin trial seems like a smart (not terribly expensive) idea.

Horse’s feet are unremarkable but I haven’t taken extensive radiographs since his PPE. His dental also went well but his teeth were definitely overdue - rads of his teeth were also clean/no signs of infection or weird roots.


You might want to get a really thorough dental and probe anything even remotely iffy. I know a horse who did some weird stuff that didn’t respond to the usual headshaking treatments. Horse coincidentally also has upper and lower airway problems. It turned out the horse had a cavity that had been there for a year or two by the time things got bad. 3 different vets/dental specialists missed it. The 4th vet found it. Took a CT scan to see really how bad the tooth was and that it had infection up to the bone. When extracted, the roots were really bad. And then after extraction, horse’s nerves went even worse for a short period to the point he nearly did serious damage to his eye by rubbing. But it did heal and then the horse was just left with airway problems but no more headshaking.

Also just heard about a horse doing weird things like this for some time and then changing personality and acting out and seriously launching his riders. After a lot of testing, the presumptive diagnosis was some kind of brain tumor based on CSF testing, and horse was euthanized.


While we are on rarities, have there been dietary changes? Between you and the previous home, or have you made changes yourself?

A recent thread here was on MSM supplements causing significant behavioral changes as a side effect in a small percentage of recipients, as an example.

As for odd behaviors, I have a mare with an extremely ticklish nose. If the halter, noseband, or fly mask happens to get too low on her face, she will go into a sneezing fit like you wouldn’t believe.

If you raise the noseband or keep things off her nose, she’s fine. But any noseband needs to be as high as possible. Forget about fly masks with the nose piece because those drive her crazy. A grazing muzzle- not happening. You can’t even loop the leap rope over her nose…

I would have your horse scoped as that should give you a better idea of what is going on in the upper sinuses.

Another option is to try a low dose dexamethasone or prednisolone and see if it reduces the coughing. But I would scope first.


While I don’t have any good insight to offer you I can at least relate heavily. My mare has been always safe and relatively sane and never had any “violent” tendencies but within the last two months she’s gotten to the point where just about any level works sends her off the deep end with her head shaking which soon leads to striking out in front of her face, and then the rearing happens either before the striking or during.
I did a trial run of gabapentin a while ago but before she’s got to this extreme and I couldn’t tell if it even had an effect or not, but now I’m rethinking to try another round.

Had her TMJ shockwaved recently trying to see if that would bring any relief, seemed that was a dead end road, but her TMJs were definitely a little jacked up so whether or not it’s all residual pain or she’s just expecting it, I’m not sure.
But I can tell you a while ago her neck was X-rayed, nothing out of the ordinary for an off-track horse but an interesting note of C6 missing both ventral tubercles was added which has always led me down the path of ECVM/C6/C7 malformation but the info is not exactly extensive out there and my vet seems to believe it’s benign which I have a hard time believing a horse with missing pieces of bone in the neck could be benign :zipper_mouth_face:
Could be worth a shot to get neck X-ray views if you haven’t yet?

FWIW though I’ve heard a couple anecdotal evidences of headshakers having some positive outcomes with feeding licorice root interestingly enough.


First, let me say that I’m sorry you’re going through this. Not sure if you’ve done any googling on headshaking, but it can have sudden onset and there are so many triggers for it (varies so much by horse) that it is one of the most frustrating conditions for owners and vets. And, it seems like headshaking can be this random, seasonal thing (that comes and goes) and sometimes where it starts up and escalates in a short period of time. It can triggered by exercise —so the horse may be completely normal in the pasture and in the stall, but start up once they are asked to work.

Typically, for headshakers, diagnostics don’t show anything specific (thus, why it is so frustrating). However, definitely have them radiograph everything in the head (ears, TMJ, etc.) and scope (standing and dynamic) to rule out anything obvious (infection in the guttural pouch for example) Also, would recommend allergy testing (not a blood test—get the dermal test, gold standard for allergy testing). When you mention all the coughing, it sounds like it may be allergy related and allergy shots may be more effective than the antihistamines.

If diagnostics don’t find an obvious reason, the first drug they will try is Cryproheptadine. I will say that it did help my HS mare, but it took about a month on it before it started to work—so give it time.

Just to point you to some resources, here is a link to a informative website developed by a vet who has done a lot of research on headshaking: http://www.headshakerinfo.org/


The cause of my headshaker’s extremely bad reactions was ulcers. Once getting the ulcers under control he only presents with some sneezing and maybe a few occasional head flips when allergies are bad. While the head shaking meds helped some he was sent into ulcer overdrive and matters became very extreme like you described with the disaster on the lounge line. It took us a very long time before realizing this was the case.


My OTTB suddenly became a headshaker at age 12 for no apparent reason, and like your horse was dangerous to ride. It was heartbreaking to see her so miserable. I was told all the usual stuff: that it’s photosensitivity, allergies, etc. No workup showed anything except her Lyme titers were astronomical. Doxcycline alone wouldn’t stop it but Doxy with Rifampin did while she was on it. (Rifampin crosses the blood/ brain barrier, Doxy doesn’t.) Vet thought it might be neurologic Lyme that affected her trigeminal nerve. It would come and go, sometimes being bad in the winter, nearly aways spring through summer.

What worked finally was giving her some human high grade CBD oil. I was using it to damp down spinal nerve compression, and it allowed me to sleep through the night and be functional days. So I gave her a 10 mg oral dose. Day 1, no response. Day 2 her headshaking was remarkably diminished. After Day 4 there was no more headshaking for the season. It took 4 doses for her to stop. It started again the following spring, but not as bad and I knew how to fix it. At that point she hadn’t been ridden in years, so she was permanently retired and bred. Her colt is now eventing under a terrific young pro and I couldn’t be more pleased for his current owners. YMMV, but it’s it’s a relatively cheap solution to trial. If you decide to try it get a good CBD product, not the gas station variety.


An emergency equine hospital veterinarian told me that head flipping (what I would describe as vertical up and down) can be a sign of ulcers or gastritis.


I had to euthanize a young horse that had trigeminal nerve pain. He occasionally would shake his head like a traditional head shaker but he also did this word thing where he would occasionally drag his head on the ground.

But, we tried nearly everything… One of the things I don’t see you trying is gabapentin?

We tried PSSM diet, antihistamines, Dex, fly masks, nose nets, all forage diet with just vitamins and minerals, treating for ulcers, testing for Lyme and EPM. We also x-rayed the skull and the neck. Nothing ever did help him. And he was injuring himself at an alarming rate and losing conditions so we eventually euthanize him after 2 years of trying everything.

Best of luck. I would definitely go to an actual clinic for a workup if possible. Maybe try and get an appointment with internal medicine.


It really pains me to admit it but one thing that has kept me up at night years later, is the possibility of Corpora Nigra cysts contributing. I did have one vet mention it during an exam but it was more of a random find. Nobody ever mentioned it even being a possibility of contributing. But later on I did read at least a few accounts of people getting surgery on their horses and it helping. I’m not sure if it would have helped my horse or not as he seem to be affected indoors and outdoors. And even with a fly mask on. But it’s worth having a vet take a look anyways.



OP, is your horse worse in the sunlight or bright sun? I had a photic head shaker who presented exactly as you describe your horse. She was diagnosed when the vet watched as I lunged her and the mare was reluctant to go, rubbing face, striking out and miserable. The vet had me put a fly mask on her to block the sun and lunge her again. The symptoms resolved by about 80 %. Maybe you could try lunging him in fly mask to see how he responds? It might give you some info to go on.


Thank you all so much for your ideas! I’ve never personally had a headshaker before and it’s incredible to me how many different “root causes” there can be to this. I appreciate all ideas and if next week’s scope yields nothing might send him somewhere for more advanced testing.

I’ll add more color based on people’s questions:
My horse has gotten regular chiropractic work done since I got him but no neck/back x-rays.
He has never been a “nose rubber” - no dragging his nose on the ground or trying to rub his nose during his meltdowns, just wants to throw his head every which way.
While we initially thought allergies, my horse has not had hives since I’ve owned him.
He behaves the same during exercise regardless of whether he’s outside in the sunlight, outside when it’s cloudy, in the indoor with the lights off/on.
He had a (long) fly mask on all of September - October and didn’t dislike wearing the nose net - it just didn’t help.

Besides the supplements/meds I listed, he is just getting hay, some grass, triple crown senior grain, and he does get 7 days of SandClear once a month (but not when there’s snow on the ground which there is now).

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I too have had success with high-quality CBD for head shaking. My mare has had seasonal (late spring-early summer) head shaking for years, seemingly triggered by allergies, not photic. I have tried many things but the CBD seems to help the most for her. She still has head shaking during that season but it is less severe and she’s more comfortable. Other times of year, nothing needed at all.

I bought my horse in MD at age 5 with no signs of head shaking. At age 6 we moved to IN and he gradually became a severe headshaker over the next 3 years, to the point of not being rideable at all some days. It seemed to start out seasonally but then became year round by year 4. No correlation to sunlight and didn’t appear to be photic.

We tried everything out there, cypro, injected TMJ, antihistamines, treated for ulcers, chiro and acupuncture, even some crazy dex protocol I found on the internet.

Then I moved back to MD (and now VA).

No more headshaking.

He still has a day or two in the spring when pollen counts are high when I see him do it out in the field. But honestly, it’s basically nothing.

I think it was driven by his environment, but I couldn’t begin to tell you “what”. I think he has some allergy issues that for whatever reason he doesn’t encounter here. All I know is that we’re not moving back to IN anytime soon so hopefully I never need to deal with it again…

ETA: just saw you’re in the northeast. Is your barn tightly closed up at night to keep it warm? I’ve always suspected the barn allergens as the main cause, although as mentioned I think he has seasonal pollen allergies as well. His barn in IN was old and mildewy and stayed really closed shut in winter exacerbating any indoor allergens.