The anal sacs are located at the 4:00 and 8:00 positions around the anus, embedded in the muscle of the anal sphincter (the muscle that closes the anus). Related glands produce a pungent yellowish secretion during defecation. Anal Sac Impaction. This disease is more commonly seen in small breed dogs and is the result of large amounts of thick anal sac secretions that cannot be expressed by the dog during defecation. The secretions build up and cause discomfort as the sac becomes distended or even infected. The only symptoms you may notice are "scooting" or rubbing the anus on the carpet or ground, and excessive licking of the anus or tail base.
Anal Sacculitis. This is inflammation of the anal sac, which can be caused by impacted anal sac secretions or bacterial infections of the anal sacs. Anal sacculitis is more painful than anal sac impaction. In addition to "scooting" and excessive licking, you may notice your pet straining to defecate, being reluctant to sit, or sitting asymmetrically.
Anal Sac Abscess. This pus-filled anal sac results from a bacterial infection. Anal sac abscesses are more painful than anal sac impactions. In addition to "scooting," excessive licking, and straining to defecate, you may also notice a red swelling near the anus, or pus dripping from an open wound near the anus if the abscess has already ruptured.
Anal Sac Tumors("apocrine gland adenocarcinomas"). These are not often painful and do not usually have redness on the overlying skin or any open wounds. They occur mostly in older female dogs (spayed as well as unspayed). They can cause an increase in blood calcium levels, which can cause clinical signs such as increased drinking and urination. They most often spread to the sublumbar lymph nodes, which are located in the abdomen right below the lumbar (lower back) vertebrae. If the lymph nodes become enlarged due to spread of the cancer, they can obstruct flow of feces by putting pressure on the colon. This may show itself as difficulty defecating or producing ribbon-like stools. Dogs with anal sac tumors can also have symptoms associated with other types of anal sac disease ("scooting," excessive licking, straining to defecate, reluctance to sit, or sitting asymmetrically).
Perianal Fistulas. This is a severe condition of the tissue around the anus, creating fistulas, or draining/oozing tracts, around the anus. It is most commonly seen in German shepherds, and is also seen in Irish setters. The cause of this difficult to control disease is unknown, but is currently thought to have an immune-mediated origin (which means that the dog's immune system is for some unknown reason attacking the tissues around the anus). German shepherds and Irish setters with symptoms of anal sac disease should also be screened for this more serious disease.