Anal Sac Disease in Dogs

The anal sacs are glands located near the anus (rectum) that produce secretions that are normally expressed during defecation. The secretions from these glands are normally pungent (in fact, very smelly) and straw-colored with brown flecks. Anal sac contents may also be expressed in times of fright (producing a terrible odor in the area).

Dogs are more commonly affected with anal sac disease than cats, and small breed dogs are more commonly affected with anal sac impaction than large breed dogs. Older female dogs are more commonly affected with anal sac tumors.

Types of anal sac disease include:

Impaction, which can lead to inflammation or infection of the anal sacs

Inflammation

Infection or abscess formation

Tumors of the sac or related glandular tissues

What to Watch For

Scooting or dragging the anus on the ground or carpet

Frequent licking of the anus or tail base

Reluctance to sit or sitting asymmetrically to avoid pressure on the painful anal sac

Straining to defecate, difficulty defecating, production of ribbon-like stools

Painful swelling at the 4 o'clock or 8 o'clock locations around the anus

Similar signs can be seen in dogs with a different disease called perianal fistula, a severe condition that causes draining tracts around the anus. The breeds that most commonly develop perianal fistulae are German shepherd dogs and Irish setters.