Headshaking - Photic
Headshaking - Photo Sensitivity
This information is designed to help those of you who have
(or think you may have) a "headshaker".
Headshaking is a distressing condition for both horse and rider. Although
being increasingly studied, very little is known about the cause of
abnormal headshaking in horses. As a result, owners are desperate for
information and that which is available is often confusing or specific to
a researcher's particular area of expertise. What follows is a
comprehensive guide to headshaking syndrome, including what behaviors your
horse may have, why they may be a headshaker and how you can help them.
the literature, headshaking is described as the sudden, intermittent and
apparently involuntary tossing of the head. It can occur to such an extent
that both horse and rider are thrown off balance or the unfortunate rider
is knocked in the face. It derives from the horse's normal and natural
impulsion to shake the head when bothered by flies in the field or when
feeling frustrated (at the start of a race).
a horse is called an abnormal headshaker when this shaking occurs under
saddle and for no apparent reason. The severity of symptoms can vary
widely between individuals, so widely that the distinction becomes unclear
between those that are classic headshakers and those that are "nodders" or
"head bobbers" (those that shake their heads more out of boredom or
frustration rather than for the reasons that follow).
the other end of the extreme, some headshakers are so dangerous and
distressed that they have to be put down. Worryingly, many headshakers are
sold on to unsuspecting owners, especially in the winter months when
headshaking is often less apparent.
Main sign - sudden and apparently
involuntary, vertical tossing of the head when ridden.
Very often occurs only after 10
minutes into exercise, i.e. when the horse is warmed up and frequently
at the trot, though headshaking can occur at any pace.
Some horses shake all year round but
the majority show a distinct seasonal pattern, the headshaking
beginning in the spring (April onwards in the UK) worsening over the
summer and easing into autumn. These horses appear symptom free over
the winter with only the occasional bout (often on bright sunny days).
Horizontal or rotary headshaking.
Headshaking at rest (i.e. when in the
field, in the stable, or when being led).
Flipping of the upper lip.
Acting as though a bee has
entered the nostrils.
Headshaking more when excited or
Snorting and or sneezing
Attempts to rub their nose on objects
whilst moving, e.g. your leg, the ground, their foreleg, stationary
Striking out with the foreleg, often
towards the muzzle or nostrils.
The horses may also
exhibit some of the following
Attempts to avoid sunlight by placing
head under the trail leaders tail, in water (including water trough) or dense
inflammation in the eyes, runny or watery nose and or eyes.
Swellings may appear on the face
Sweat patches appear on the body
Stumbling, even falling
Breathing may be labored or sound odd
They may approach seeming
to be out of sorts, peculiar, at times either "spaced out" or
staring into space. Horse may even seem panic filled and out of control.
Could also appear to be
or dopey and lethargic.
They may even 'clamp' their nostrils
After an attack your
horse may continue to:
Sneeze or snort
Rub its nose on objects, e.g. you!,
stable doors, walls, or posts.
Display a runny nose or
Appear uncomfortable, distressed or
References (Lane & Mair
There is not one, sole
cause of headshaking. It is a 'presenting sign' of disease, and excessive
headshaking is merely an expression that something is wrong and/or
irritating the horse. Headshaking has been associated with nearly 60
diseases and conditions, including,
EPM, ear mites, eye problems, guttural pouch mycosis and
vasomotor rhinitis (Cook 1980b, Lane & Mair 1987). Usually these
diseases will show other symptoms along with the headshaking that can be
used to diagnose the disease.
However, many of you will
have checked your horse out with the vet and they may have found no
apparent signs of disease. Their behavior may also fit into a common
pattern - see clinical signs. In this case, your horse may be what is
commonly referred to as an idiopathic headshaker (Lane & Mair 1987),
which is treated very much like a disease in itself, there being no other
apparent signs of disease only the headshaking.
Immediate causes or
triggers for idiopathic headshaking may be riding near oil seed rape
fields in bloom or being in bright sunlight and are what owners often
manage to identify themselves. Underlying causes, the real reason the
horse is headshaking, are harder to establish for example, allergic
There is also a difference
between the cause; for example, allergic rhinitis and potential risk
factor such as being over exposed to an allergen at an earlier stage. An
identification of potential risk factors may help reduce the incidence of
each different kind of headshaking. At the moment little is known about
how the range of symptoms that the horse may suffer from can differ,
depending on the cause. You may see aspects of your horse's behavior in
all of the below descriptions.
My research focuses on ways
in which we can clearly define potentially distinct types of idiopathic
headshaker. This is necessary before we can hope to find meaningful
treatments and identify risk factors. It is recommended that you get your
veterinarian to thoroughly look over your horse. This is especially
important if its behavior is severe or different from what has so far been
described. It may also be worth checking that its back is not painful and
your tack is not hurting either.
I've checked him out
and found nothing - why?
mechanisms causing the headshaking maybe something we can't easily see,
e.g. allergic reactions or nerve sensitivity.
Riding near hedgerows, trees, airable
crops especially oilseed rape
(during the pollen season, or possibly
when being sprayed).
Midges and small flies annoying the
Being touched in a sensitive area
(muzzle, poll or face), even snowflakes or light rain may set the
Stress - at shows, being put with
Loud or sharp noises.
Causes - Allergic
horses may be suffering from an allergy similar to hay fever. Things that
may trigger them off include riding them through arable crops, trees, etc.
They may show an obvious seasonal pattern but together with cross
pollination factors and a general worsening/hypersensitivity of the
condition, they may also do it at other times. They may sneeze or snort,
their nose may run and eyes look sore. They may seem worse in bright
sunshine as humans often do when suffering from hay fever.
References Lane & Mair
such as pollen, oilseed rape volatiles, dust, etc get into the horse's
nose. An allergic reaction occurs in the mucus membranes that line the
inside of its nasal passages. Inflammation and creation of mucus
stimulates irritant nerve receptors in the nasal passages, which irritate
the horse, and so it throws its head up.
can I do?
Look for common factors and
coincidences occurring at the time your horse has a headshaking attack
in order to work out what may be the offending allergen.
Avoidance tactics, i.e. avoid these!
Consult your vet. There may be some
drugs that will help which only vets are qualified to administer.
Try using a nose net, available from
equilibrium, your local saddler or make your own out of the foot of a
pair of tights tied to the noseband. It may act to filter out pollens,
but is more likely to act as a counter stimulant.
Allergy neutralization - React
Clinic, or consult an alternative vet.
types of headshakers may be easier to spot and this certainly seems to a
major cause of headshaking in the US. These horses are usually obviously
worse in sunlight and may actively hide their heads in the shade or in a
companion's tail. Their eyes may appear sore and water as well. Try
lunging your horse with a blindfold on or indoors or at night to see if
this is the case. If his headshaking is much improved then he maybe
reacting to the sunshine.
References John Madigan et al (1995).
horse may be suffering from a phenomenon similar to the photic sneeze
syndrome in humans. Stimulation of the optic nerves (behind the eye) by
light can also cause stimulation in other nerves within the head.
Reactions that follow include constriction of the pupils and in some cases
lacrimation (watery eyes) and nasal membrane reddening. The irritation of
mucus and alterations in blood flow within the nasal passages may cause
the horse to shake its head, snort and sneeze.
an additional theory as well: These horses may have had some previous
damage to the muzzle area and their threshold to pain caused by this
'referred stimulation' has been lowered, or they have been in contact with
the EHV1 flu-virus (or possibly the vaccine) when younger. Sunlight,
stress or exercise may make this virus more active and it causes increased
stimulation of the trigeminal nerve, which conducts sensation from the
muzzle to the brain. The horse starts headshaking as a result.
can I do?
Consult your vet. Possible drugs
which only they can advise you about, for example, Cyproheptadine or
Periactin. Melatonin may help as hormonal imbalances may make the
horse more sensitive to sunshine in the summer - speak to your vet
Try using a face net to shield your
horses eyes and face from the sunlight
More extreme cases will need total
protection from the sun (but with vision unimpaired) see
Standard Guardian Mask
with 95% Sunshades
Avoidance tactics - Ride him indoors
if you can, if not at night (but use your common sense!), sometimes
dawn or dusk is still okay.
Provide shelter from the sun for his own comfort when
not being ridden
horse may not show any clear seasonal patterns to his headshaking, or his
headshaking may only occur when being ridden. If he ceases to shake as
much when not under saddle or with a bit in his mouth then the cause of
his headshaking may be bit pressure causing nerve pain. A good test for
this is to lunge your horse in a head collar only. However, your horse may
continue to experience 'ghost' feelings of pain for sometime after the bit
is removed or the headshaking may have turned into a habit and this test
may need to be repeated several times.
what we put our horses through, it is surprising how many allow us to tack
them up and ride them in all sorts of strange ways without problem or
complaint. However, Professor Cook at Tufts University believes that by
placing a bit in the horse's mouth we are putting abnormal constraints on
the horse. Not only does putting something in its mouth and asking it to
exercise confuse the horse (it might think it should be eating!), but also
constant pressure by the bit may be causing pain in the mandibular branch
of the trigeminal nerve.
horse may be headshaking due to intolerance of this confusing lump of
metal in its mouth or because the bit is directly causing neuralgia (nerve
pain). Add to this the possibility that the bit increases the likelihood
of poll flexion (bending of the neck from the poll) which makes breathing
harder and it is not so surprising that we occasionally get problems like
headshaking. Headshakers suffering because of the bit may still show
seasonal patterns as they may be worked more in the summer or the
increased heat may exacerbate the problem.
References (Cook 1992 & 1999).
can I do?
Cook advocates the use of a bitless bridle and claims excellent results
for all headshakers. Whether the bit is the direct cause or not, it
certainly makes sense to consider using this more humane bridle anyway.
Maybe one day all horses will be in one and bits will be a thing of the
horse may just have a sensitive muzzle and so anything, e.g. rain, snow,
flies or sweat from exercise touching him in this area may set him off
nerves in your horse's muzzle may be inherently hypersensitive or may have
been damaged in the past causing them to be more sensitive than they were.
Small objects touching the muzzle may stimulate the sensory nerves causing
irritation, which the horse reacts to by throwing its head up. Stress may
also lower the horse's threshold to pain and irritation.
can I do?
You may find your horse benefits from
a nose net, not for its filtering abilities but because it acts as a
counter stimulant. Some horses are desensitized by using this and will
not shake even if the initial irritant appears.
fly fringe or Nose Shaker, similar to what you put on the head collar may work just as
well if placed lower down, hanging from the nose band.
Causes - Behavioral problems
As explained before, there
is some confusion as to what is and what isn't a headshaker, especially
among owners who haven't yet consulted their vet because the symptoms
aren't that bad.
Just because your horse so
far doesn't show any seasonal patterns and you haven't noticed any other
patterns doesn't mean he isn't an idiopathic headshaker and is a 'bad'
horse. He may have been a seasonal headshaker in the past and his symptoms
have worsened so that he shakes intermittently all year round. His
headshaking may have also turned into somewhat of a habit as well. You may
find that he shakes his head more when annoyed, frustrated, stressed or
conversely, bored. His shaking may be reduced by making him concentrate,
i.e. jumping or interesting flat work, but this is often also the case
with allergic headshakers (if you think about it you can often stop
sneezing if your mind is taken off it).
However, if his head
movements are more rhythmical, occur towards the end of a ride, when you
feel he might be bored or occur at rest in the stable, and he does not
show any signs of irritation/inflammation, then he may have a purely
What can I do?
If you feel the only reason he shakes
is frustration, stress or in annoyance, then consider the situations
in which he shakes and see if you and another experienced horse rider
may be able to find solutions to these situations.
Do not force him
into behaving by using brute force/heavy discipline, nor do we suggest
you use a stronger bit or reins to control him. He is headshaking for
a reason and not just to make life difficult for you!
He may be happier in a bitless bridle.
Don't take him to places where he
gets stressed or place him in stressful situations.
If its boredom, make his life or
riding lessons more interesting!
Consider re-schooling him, using
non-physical, non-confrontational techniques.
animal communicators and trainers near you, or ask your vet or riding
school to recommend someone.
many other causes...
are a lot of diseases and conditions that may cause a horse to headshake.
Respiratory problems and infections
resulting in blocked airways, e.g. guttural pouch mycosis
Central neurological problems and
diseases e.g. EPM
Hormonal problems, e.g. Cushing's
Ear mite infestations and
or Middle ear problems
Usually these are rarely the sole
cause of the headshaking, as upon correction of the problem the
headshaking may re-occur. But this doesn't mean that the problem
itself should be ignored! You should consult your vet to rule these
Techniques that owners have
reported having helped their horse
- either manufactured ones (see your saddler) or home made ones with a
pair of tights or pantyhose. Our work showed that these at least partially helped
over 60% of horses that had tried it. They may not filter out
allergens as previously thought, but act as a counter stimulant, a
kind of soothing rub, which makes the horse ignore any other itches.
You will probably find that your horse either loves or hates it. If he
does take to it you may find that you can now ride him with it on as
you did before.
Fly fringes over the nose
- may work like the nose net but are more aesthetically pleasing - try
taking the fly fringe and putting on the nose band so it hangs over
the horse's nostrils.
- nearly 40% of owners who had tried this felt it at least partially
helped the horse. Ask your vet to recommend a homeopathic vet to you.
Or see Capstar or Hilton Herbs. You must persist with your homeopathy
treatment, it is not necessarily a quick fix (it may take months).
- with 95% Sunshades from Guardian Mask Particularly worth a try if you think your horse suffers
from the UV rays of the sun.
Ride indoors (to avoid sunlight, wind
and the majority of allergens).
Adjust or change your tack, look for
'kinder' alternatives rather than harsher ones, consider the bitless
Move your horse to a different
field/livery, esp. worth it if you live right next to a rape field or
Try riding in a different area if you
can't move, e.g. on the beach, on roads, grassed areas.
Ride early morning/late evening.
Try putting an ear net over his ear,
especially if he seems bothered by flies in this area.
Herbal supplements, for breathing and
allergies (Hackaway or Freeway) or temperament (Response or Temperament
) from Hilton Herbs, for allergies try Echinacea from
Equine Health & Herbal.
Change the level or type of work he
does, he may prefer to work less or more.
Olive oil & vinegar on the nose.
Aromatherapy (keeps flies away too!)
- 20ml of sweet almond oil mixed with 5 drops each of tea tree,
lavender & Geranium oil, shaken and applied to horse's forelock,
muzzle, jaw line and base of ears (Mrs. S. Clegg). Try also
citronella, Vicks or eucalyptus oil as a fly repellent. Be careful
with these oils as some horses have very sensitive skin and may react
adversely. Consult your vet first!
Try putting a high sunblock on his
Try cutting sugars out of his diet -
check with your vet first.
Some people have tried magnesium,
phosphorus or Vitamin C supplements. Consult your vet first!
Soaking hay to reduce the possibility
of hay allergies.
Friars balsam to clear up breathing
Electrotherapy on the back.
remember to seek the advice of your Veterinarian before treatment.