The anal glands (more appropriately, anal sacs) are two small grape shaped pouches that open beside the anus in all carnivores (except the bear). In dogs they are about 1 cm in diameter and open, via a short duct, at about the 4 o'clock and 8 o'clock position of the anus. In cats, the sacs are smaller and open slightly more externally relative to the anus. The sacs are lined with sebaceous and serous glands which produce the foul smelling secretions. The secretions are normally expressed when the animal has a bowel movement (defecates). Occasionally, if the dog or cat is nervous, excited, startled or injured, the sacs can discharge spontaneously. Normally, the fluid produced by the glands is a clearish or pale yellow-brown in color. When diseased, the secretions can become thick, pasty brown; thinned creamy yellow or yellow-green; or thick creamy red-brown in color.
Dogs are more prone to have anal gland problems than cats. Small dog breeds, such as miniature poodles, toy poodles and Chihuahuas, are reportedly predisposed to having problems. No age or sex predispositions have been described.
Several different types of problems can occur involving the anal sacs. These include obstruction, inflammation, infection, and even tumor formation. The most common anal sac problems are:
•Impaction—failure of the anal sacs to express, often resulting in drying out and hardening (inspissation) of the contents, which then accumulate, causing discomfort.
• Sacculitis—inflammation of the anal sacs. Usually related to impaction or abscessation but occasionally occurs on its own.
•Abscessation—bacterial infection of the sacs, usually following an impaction. Inflammation and pain in the area will be present. The abscess can sometimes rupture, draining purulent material (pus) and blood, usually just below and to the side of the anus.
In most pets with anal sac problems, the owner will notice a few common signs. The first is the classic "scooting", where the dog will drag their hind end across the floor in attempt to itch or relieve discomfort in the area. Dogs and cats may also attempt to lick the area frequently or turn their heads suddenly as if being "bitten" by something. Others may just seem “bothered” by nonspecific discomfort. You might even notice a change in their stool habits. This can be by a variation in the shape of the stool (thin, ribbon-like) or pain when attempting to have a bowel movement.
On physical examination, we will evaluate the anal area and perform a rectal exam to determine the condition of the anal sacs. Usually we will be able to express the material by applying light pressure. Rarely, this is too painful for the pet and sedation may be necessary. If the anal sac (or sacs) have abscessed, an open wound is usually found adjacent to the anus with evidence of pus and/or blood. Various degrees of inflammation may be present and we will evaluate that along with the color and consistency of the discharge expressed to assess the problem.
Luckily, anal sac impaction or abscessation generally is not a serious illness. It can, however, be a chronic problem and can reoccur frequently, causing discomfort. Many dogs are affected for no apparent reason. There are no preventative measures to guarantee that the problem never returns. The most important thing is to monitor your pet’s behavior and defecation habits and contact us if constipation or pain becomes apparent.
In the case of impaction, we can often help by expressing the anal sac material. During a rectal palpation, pressure is applied the sac to empty it. If this is painful or the material is too hard, sedation of the dog or cat may be needed so the emptying can be done without discomfort. Occasionally, a small tube (catheter) is placed into the sac through the pore, and the sac is irrigated with saline to flush it. This can help soften very hard material if present. Medication may also be instilled into the anal glands to help reduce inflammation and treat any infection. Depending on the degree of inflammation, we may prescribe oral antibiotics or anti-inflammatories.
Often, the first sign of an anal sac abscess is when you see pus and/or blood draining from the anal area beneath the tail after the abscess has ruptured through the skin. Owners will often see this on the pets hind end or may find blood areas on the carpet or other resting area. If the abscess has not yet burst, we will express the sac as best as possible and instill medication into the sac. Rarely, we will lance the abscess in an attempt to help it drain the infected fluid. Usually the abscessed sac will be flushed with sterile saline and have medication instilled into it. Whether the abscess is lanced or ruptured, it is important that it remain open for as long as possible to allow the infected material to drain. Warm compresses can help and we may recommend that you apply warm-packs to the area two or more times daily. A good way to do this is to use a warm wet washcloth (heated by holding under warm water) and hold in place over the affected area for five to ten minutes. It is important to test the temperature of the washcloth prior to placement to make sure that it is not too hot. Oral antibiotics and anti-inflammatory medications will likely be prescribed.
If impaction or abscessation recurs, the anal sacs may have to be expressed repeatedly. Some dogs require this procedure every one to two weeks after having an episode of impaction, gradually decreasing the frequency to whenever necessary.
There have been some anecdotal reports that changing a pets diet to one that is high in fiber may help the anal sacs express on their own with normal bowel movements. We may recommend a different dog food or additives such as pumpkin, bran or Metamucil(R) to your pet’s regular food.
In cases where the anal sacs become impacted or abscessed often, it may be advised to have the anal sacs removed surgically (anal sacculectomy). We will usually refer these patients to the Board Certified surgeons to have the best opportunity for a successful outcome. Although uncommon, there is always a small risk of complications such as infection or compromise of the anal sphincter, resulting in fecal incontinence. It is a delicate but short procedure, and the patient usually goes home the same day with some home care such as warm compresses and pain medication and antibiotics.
•Give all medications as directed •Become familiar with your pet’s defecation habits. Be aware of any changes in stool shape (thin and pencil-like) or behavior (pain or straining to defecate, scooting, looking anxiously at hind end). •Have your pet examined if you notice repeated “scooting”, recurrent licking at the anal area, or any sign of discomfort when defecating.
•Don’t wait until the problem recurs to have a recheck appointment if your pet has had an anal sac problem requiring treatment. Since anal sac problems often return, it is best to have us continue to monitor your pet until the anal sacs are functioning normally and not causing symptoms.
When to Give Us a Call
•If you are unable to give any medication prescribed as directed. •If you notice signs of pain or straining to defecate.
• If your pet continues to scoot or have other symptoms or you notice irritation or redness on the skin.
Signs to Watch For
•Scooting, licking at the hind end, pain on defecation, swelling or drainage around the anus.
•We will recheck your pet based on the severity of the case. As mentioned, many dogs require routine expression of their anal sacs. The frequency will depend on the patient.
• Some other more serious conditions can result in similar symptoms and should not be mistaken for anal sac impaction or abscessation:
Perianal fistulas—a severe, on-going disease of the area around the anus. Multiple draining tracts are present, which are deep fissures in the skin surrounding the anus. The anal sacs themselves are not involved. German shepherds are most commonly affected.
Anal sac tumors (adenocarcinomas)—cancerous tumor of the anal sac, occurring more commonly in older dogs. These tumors can often spread to regional lymph nodes, which can enlarge and obstruct the path of feces. It is generally recommended to have any mass occurring in the anal area removed. Anal sac tumors are much less common than anal sac impaction or abscesses.