DOGS · Condition guide
Anal sac disease in dogs: impaction, infection, and rupture
Anal sac disease affects roughly 1 in 20 dogs each year — high enough to be in the UK top-10 of primary-care diagnoses, but most owners only learn about it the first time their dog starts scooting across the carpet. The sacs sit at the 4 and 8 o'clock positions next to the anus and normally empty during defecation. When they don't, the secretion thickens, becomes irritating, and eventually infected (anal sacculitis) — and in the worst cases ruptures through the skin as a painful abscess.
Repeated impactions are common in small breeds, overweight dogs, and dogs with soft stools. Most cases resolve with manual expression and (if infected) antibiotics. Less common but important: anal sac adenocarcinoma is a malignant tumour that produces a firm mass at the sac site — every persistent or unilateral swelling deserves a careful exam, not just another expression.
What vets typically check for
- Digital rectal exam to assess sac size, contents, and any firm masses.
- Cytology of expressed contents if infection or atypia is suspected.
- Fine-needle aspirate of any firm swelling — rule out anal sac adenocarcinoma.
- Bloodwork including ionised calcium when malignancy is suspected (paraneoplastic hypercalcemia).
- Surgical sacculectomy for chronic recurrent disease or confirmed neoplasia.
Not a replacement for veterinary care. Use this to walk into the conversation prepared, not to self-diagnose.
Real cases from the veterinary literature
Peer-reviewed reports our semantic search surfaces for Anal sac disease in dogs. Click into any case for the full abstract — or run a personalised search with your pet's exact details.
- Investigation of the "R" tumor margin classification and prognostic factors in apocrine gland anal sac adenocarcinoma of dogs.
Veterinary surgery : VS · 2026 · Australia
A 7-year-old male dog with anal sac cancer underwent surgery to remove the tumor. After the surgery, the tumor margins were examined, and 75.7% of the dogs had clean margins, which means a lower chance of the cancer coming back. However, dogs with certain factors like high calcium levels before surgery or existing metastases had shorter survival times. Overall, the average surv
- Analysis of Dual-Energy Computed Tomography Imaging for the Evaluation of Lymph Node Metastasis in Canine Anal Sac Gland Adenocarcinoma: A Case Report.
Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association · 2026 · Japan
A 9-year-old neutered male miniature schnauzer was brought in because he was drinking a lot of water and urinating frequently. Tests showed he had high calcium levels and a mass in his left anal gland, along with swollen lymph nodes nearby. The mass was surgically removed, and it was diagnosed as anal sac gland adenocarcinoma, which had spread to the lymph nodes. The imaging te
- Efficacy of an oral chew containing fibre and Bacillus velezensis C-3102 in the management of anal sac impaction in dogs.
Veterinary dermatology · 2025 · Spain
A group of 35 dogs with anal sac impaction, a common issue that can cause discomfort and require manual emptying, were studied to see if a special chew containing probiotics and fiber could help. Over 90 days, 22 dogs received the chew while 13 did not. The dogs that took the chew had a much lower rate of needing manual expression of their anal sacs compared to those that didn’
- Retrospective evaluation of surgical outcomes using traditional, internal obturator muscle flap, and sacroischial sling technique for canine perineal hernia repair.
Journal Article · 2025
A group of 87 male and female dogs with perineal hernias underwent surgery using three different techniques to see which worked best. The sacroischial sling method had the highest success rate and the lowest complication rate compared to the traditional method and the internal obturator muscle flap. While the internal obturator muscle flap showed a high success rate, it had mor
- Management of Multiple Perianal Apocrine Hamartomas in a Poodle Dog Using Carbon Dioxide Laser.
Veterinary medicine and science · 2025 · South Korea
A 7-year-old neutered male Poodle was brought in because he had multiple itchy bumps around his rear end. After examining the bumps, the vet found that the glands in that area were enlarged and inflamed. To treat this, the vet used a carbon dioxide laser to remove the growths instead of doing traditional surgery. One month later, the Poodle had fully healed, and his itching had
- Complications associated with modified closed anal sacculectomies using monopolar electrosurgery in 113 dogs.
Journal of the American Veterinary Medical Association · 2025
A group of 113 dogs underwent a surgery called modified closed anal sacculectomy, which involved using a special type of electrosurgery. After the procedure, about 15% of the dogs showed some swelling and bruising on the first day, while 9% had issues like incision discharge later on. Most of these complications were minor and resolved on their own. However, if the surgery didn
Frequently asked questions
- How often should I have the glands expressed?
- Only when there's a clinical sign — scooting, licking, swelling, or discomfort. Routine prophylactic expression in dogs that aren't symptomatic isn't recommended; it can actually irritate the sacs and trigger problems.
- Could it be cancer instead of just impaction?
- Yes. Anal sac adenocarcinoma is uncommon but serious. Warning signs are a firm, unilateral swelling that doesn't go away with expression, persistent straining, or high blood calcium on bloodwork. Always have a persistent or asymmetric mass at the sac aspirated.
- Does diet help?
- Sometimes — adding fibre (pumpkin, psyllium, or a high-fibre prescription diet) bulks the stool so it puts more pressure on the sacs during defecation and helps them empty naturally. Weight loss helps in overweight dogs.