species: click on a picture:
The pinna is composed of a flared cartilaginous extension
of the annular cartilage covered with skin. The relatively
hairless skin of the concave side is more tighly adherent
than the haired skin of the convex side. The pinna is
supplied by branches of the external carotid artery and the
great auricular artery which branches and courses up the
convex aspect of the pinna. The concave aspect is supplied
by branches which pass through foramina in the middle third
of the pinna or which wrap around the pinnal margins. This
pattern of vascular supply explains the tendency for pinnal
lacerations to bleed profusely and is the reason for
placing mattress sutures parallel to the long axis of the
pinna when dealing with aural hematoma.
The underlying cause of aural hematoma is unknown. Various
factors heve been proposed to account for the pathogenesis
of the lesion itself and for the undelying cause which
incites the process: most of these have been shown
subsequently to be inadequate in some degree.
Association with Otodectes
60 percent of dogs and almost 80 percent of cats with aural
hematoma were affected with Otodectes cynotis.
Association with otitis
70 percent of the dogs and 80 percent of cats were affected
with otitis externa, caused by infections or foreign bodies
(foxtails) in the external ear canal
Association with trauma
This is most frequently cited as the cause of aural
Some peaople propose that aural hematoma had an
immune-mediated, possibly autoimmune, cause.
Association with underlying
Many cases of aural hematoma appear to be associated with
underlying hypersensitivity and in atopy, the most common
canine hypersensitivity, lesions are often present on the
concave aspect of the pinnae. Certainly, otitis externa is
a common manifestation of atopy, as is pruritus of the head
The symptoms of an aural hematoma are obvious. Depending on
the severity of the problem there will be swelling,
sometimes extensive. Almost every pet will either be
holding the head to one side or either shaking and pawing
at the affected side.
In a significant
number of cases we can alleviate the hematoma by removing
the fluid and injecting cortisone into the ear. The problem
is that a space is left behind when the fluid is removed
and this space may refill with more fluid.
This treatment is usually repeated in one week, although
some cases are healed after the first week of therapy. Pets
that don’t heal after the second treatment need surgical
The initial cause of the hematoma, usually an ear
infection, will be treated simultaneously.
It is advantageous in most cases to use medical therapy
first because there is no need for general anesthesia,
there is minimal discomfort to your pet, and the cost is
less than surgical correction. Surgical treatment is used
in those situations in which the problem is not corrected
with medical therapy.
Of course the ear infection must be treated along with the
There are several surgical techniques. The most commonly
performed procedure is draining of the hematoma of fluid
and blood clots. To prevent the hematoma from refilling
with fluid, multiple sutures are placed in the hematoma
space either vertically or horizontally, either partly
through or completely through the ear flap, with or without
ear cartilage removal. Sometimes bandages are applied
post-operatively, sometimes not. Sutures are
generally left in place for 3 weeks to allow good scarring
to take place so that refilling will not occur.
None of these techniques achieve a rapid resolution and all
relatively expensive in financial terms for what the owner
might consider simply a large ‘blood blister’. Good
communication with the owner is important.
we do nothing?
If left alone,
an ear hematoma will resolve by itself. The fluid will be
re-absorbed back into the body and the ear flap will again
be flat. The problem is that a lot of scarring is
associated with this process and the ear is often not
cosmetically appealing afterwards (a “cauliflower” ear). It
can also take several months to resolve a large hematoma
which may be uncomfortable for the pet. If the
patient is a poor anesthetic risk it is certainly
reasonable to for go surgery.