What Are
Anal Sacs,
Why Do Dogs Have Them and
How Do I Express Them?
By Dr. Boyd Harrell
A question pet owners
often ask is “Just exactly what are anal sacs and what function do they have?”
This article will attempt to answer that question in a way that will allow the
pet professional to give an intelligent answer to the client and to offer
assistance in relieving discomfort from impacted anal sacs. The terms anal
glands and anal sacs are often used interchangeably. The two are closely
related and distinctly different. Typically when one refers to the anal glands,
it is really the anal sacs they are speaking about. Anal sacs are two hollow
structures that serve as a reservoir for an oily secretion emptied directly
into them by a heavy population of anal glands in the lining of the sacs. The
glands are microscopic while the sacs are large enough to see or feel.
These sacs vary in size proportionate to the breed. They range from pea size or
smaller in the
Their purpose seems to be for individual identification and territorial
marking. The odor is distinct for each individual and is a reason for one dog
to sniff beneath the tail of another. When a bowel movement passes over the
glands, the pressure will cause the release of some secretion, thus marking the
elimination and telling others who was here. Occasionally during excitement or
fright the anal tone increases and the sacs may empty, releasing an oil that has a strong foul fish-like odor, that much like
skunk odor, lingers for a long time and is difficult to wash away. Anal sacs in
the skunk are modified to be voluntarily released and produce a larger volume
and stronger odor than the dog. These sacs have no real useful or vital
function for the pet dog and are often problematic. If the sacs become overly
full or inflamed, the dog may suffer considerable discomfort.
Impaction is most common and happens when the secretion becomes trapped
stretching and engorging the sacs. Toy breeds and other dogs under 20 pounds
are especially prone to impaction. In contrast, larger dogs and sporting dogs
rarely suffer from impaction. Possible causes of impaction include a secretion
that is too thick to pass through the narrow ducts. Normal secretion is
brownish in color and light to heavy oil consistency. Sometimes the secretion
is normal and the ducts are too small. The ducts may be inherently narrow or
they may become narrow due to scarring from repeated or long-term inflammation.
Another contribution to impaction may be weak or sparse muscle fibers
surrounding the sacs giving poor assistance to emptying. This is especially
common in obese dogs and dogs with generally poor muscle tone. Sometimes the
glands become overly active and simply produce too much secretion, overfilling
the sacs. Impacted anal sacs are usually relieved by digitally expressing the
contents and the procedure will be detailed later in this article.
Sacculitis is when bacteria proliferate in the sacs,
usually entering from feces passing over the duct. The secretion turns
yellowish with or without blood and the condition is called anal sacculitis. This secretion may leak onto the surrounding
area, causing the anus and underside of the tail to become moist and sticky.
Sometimes blood is seen on the skin or streaked onto the bowel movement.
Veterinary care should be recommended for these patients and may include
antibiotics, flushing or infusing the glands and pain control.
Abscesses are a more advanced stage of sacculitis
when puss is trapped in the sac. This causes the area to become warm, reddened
and very painful. Eventually it may break through
the skin over the sac, exuding its contents made up of a creamy or bloody thick
material. Some abscesses need to be lanced to establish drainage and relieve
patient discomfort. This condition is so painful that the dog may try to escape
or bite when the area is approached or touched. These sacs are too painful to
be expressed and veterinary care including antibiotics, antiseptic irrigation
and pain control is indicated.
The last category of problems with the anal glands is neoplasia
or tumors. Tumors of the glands are rare and can be a serious problem. The
tumors may grow locally, interfering with normal anal tone and function. They
may also spread or metastasize to other parts of the body, causing organ
dysfunction and even death.
If anal sac problems of any description persist then surgical excision is
recommended. This generally gives a permanent cure though there are infrequent
complications the owner should be aware of. One possible complication is fecal
incontinence or poor anal tone. Although infrequent, these signs may be
permanent. An open draining tract or fistula may result if any portion of the
sac wall is not completely removed. This condition can often be repaired with a
follow up surgery to excise the fistulas, tract and remnants of the anal sac.
Signs of anal sac disease may be similar for all the categories, with impaction
being the most frequently seen problem. Common signs of impaction include
excessive licking and dragging the bottom on the ground, often referred to as
scooting. This scooting behavior may help to relieve some itching and tingling
sensations and sometimes provides enough pressure on the glands to express
them. This scooting however often adds to the burden by causing additional
inflammation and pain. Offensive odor results when some of the secretion leaks
onto the pet or the environment. Sometimes owners will describe dark colored,
foul smelling spots on their carpet or upholstery caused by the leakage.
Groomers should educate themselves so as to recognize the various categories of
anal sac problems and be able to give good advice to the pet owner while being
a pet advocate. Anal gland impaction is the only category that groomers should
attempt to rectify; all other categories require immediate veterinary care.
Some groomers may choose to express impacted anal glands as a valued service in
areas where it is legal and does not violate the state veterinary practice act.
Following is a description on how to properly express the anal sacs.
Expressing Anal Sacs
There are two types of anal sac expression, external and internal. The external
technique is done from the outside and is the most common method used. The
internal technique is done with a lubricated gloved finger inserted into the
rectum. This technique may be preferred in some heavy dogs, very tense dogs or
dogs with poor muscle tone when the sacs can’t
be easily trapped with the external method.
Since expressing the anal glands releases an objectionable odor, consider doing
this in the tub and before bathing so that the area can be quickly flushed with
large volumes of water and cleaned immediately. If the sacs are to be expressed
on a dog that can not be bathed or showered down afterward then cotton or gauze
soaked in a safe odor neutralizer such as chlorine dioxide should be used to
trap the secretion and wipe down the anal area. The operator should wear gloves
with either technique.
Start by raising the tail to a vertical position. The sacs will be a fluid
filled compressible round structure and can usually be felt near the anus at
the four and eight o’clock positions. Position the index finger and thumb to
the outer edge and bottom of the sacs so as to form a C with the hand. The idea
is to force the sacs in an upward and backward direction with the thumb and
index finger. Be sure to cover the area with gauze or cotton before expressing.
The contents will be under pressure and can shoot great distances very quickly!
(You definitely don’t want to be in the line of fire.)
While
pressing against the sac, begin to close the thumb and finger at the tips first
then flattening out both so as to squeeze or milk out the sacs. More than one
attempt may be necessary to completely empty both glands. Take care not to
squeeze and block off the ducts during the procedure.
Internal expression of the anal sacs also starts with an erect tail. The gloved
index finger is inserted into the rectum past the muscles of the anal sphincter
then curled back to find the sac. The sacs are located one at a time and
squeezed or milked out with the thumb on the outside and index finger on the
inside in a manner similar to the way the glands were expressed externally. The
internal method allows more direct pressure to be placed on the sac and is used
when the external technique fails. Heavy dogs, very tense dogs and dogs with
very thick secretions or very narrow ducts may need internal expression of the
sacs.
With either technique one must use only reasonable pressure on the sacs to
prevent them from rupturing. Rupturing does not occur often and demands
immediate veterinary attention when it does happen. With a little practice you
will be able to express the anal sacs for most dogs you see. This is a valuable
and frequently requested service by dog owners. There is some debate over when
the anal sacs should be expressed. Some people believe that the sacs should be
expressed only if the dog is showing signs. Another group feels that high risk
dogs, like those under 20 pounds, should be expressed routinely while leaving
the larger dogs alone unless they are having trouble.
Dr. Boyd Harrell is currently practicing pet medicine in central