The anal glands on both sides of the anus are usually drained naturally when your dog has a bowel movement, but sometimes the fluid becomes too thick to be expressed and it will become impacted clogged up. After the anal gland has been impacted for a while, it becomes infected and swollen. Finally, the infection will cause an abscess that is very painful for your dog. You will need to take your dog to the veterinarian so he can drain and clean the anal gland. The veterinarian will probably give your dog antibiotics in this case. The sooner you get this painful illness treated, the better the outcome will be for both you and your dog.
Anal sac disease is the most common disease entity of the anal region in dogs. Small breeds are predisposed; large or giant breeds are rarely affected. In cats, the most common form of anal sac disease is impaction. Anal sacs may become impacted, infected, abscessed, or neoplastic. Failure of the sacs to express during defecation, poor muscle tone in obese dogs, and generalized seborrhea which produces glandular hypersecretion lead to retention of sac contents.
The literature about the anal sacs of healthy dogs and the pathogenesis, diagnosis and therapy of anal sac impaction and sacculitis are reviewed. Knowledge about the physiological role of the anal sacs is still confusing. The colour and consistency of the anal sac contents are variable in healthy dogs and there are no pathognomonic signs of anal sac impaction or sacculitis. The wide variation in macroscopic detail of anal sac secretions may give rise to misinterpretation and thus overdiagnosis of sacculitis. Other diseases such as vaginitis, flea allergy, atopy, proctitis, parasites and perianal fistulae can lead to similar signs and must be eliminated from the differential diagnosis before the anal sacs are incited as the cause of the signs.