Anal Gland Disease

The most recognizable sign is scooting — a dog or cat dragging its rear end across the floor — though this behavior can also indicate other problems such as intestinal parasites or perianal irritation. Additional signs of anal gland disease include:

• Scooting or rubbing the rear end on carpets, grass, or furniture
• Licking or biting at the base of the tail or around the anus
• A strong, fishy odor — from expressed anal gland secretion or a leaking abscess
• Swelling, redness, or a visible soft lump beside the anus (abscess or cellulitis)
• Straining to defecate or pain when sitting
• A visible opening in the skin beside the anus discharging brown or bloody fluid (ruptured abscess)
• In anal sac adenocarcinoma: a firm mass that may not cause obvious discomfort initially; symptoms of hypercalcemia (excessive thirst, urination, lethargy) in some cases

A ruptured anal gland abscess is painful and looks alarming but is rarely life-threatening — it does require prompt cleaning and antibiotic treatment to heal properly.

Anal gland impaction occurs when the duct that allows the gland to drain becomes blocked or the secretions are too thick to express naturally. Contributing factors include:

• Soft or loose stools — firm stool passing through the anal opening normally applies pressure that expresses the glands; chronic soft stools prevent this natural emptying
• Obesity — excess perianal fat changes the anatomy and prevents normal expression
• Allergies — environmental and food allergies frequently cause anal gland inflammation and are a common driver of recurrent impaction in dogs
• Small breed predisposition — Toy Poodles, Chihuahuas, Dachshunds, Beagles, and Cocker Spaniels have narrow gland ducts relative to gland size
• Anatomical abnormalities — a narrow duct opening from birth can predispose to chronic problems
• Anal sac adenocarcinoma — the cause is unknown; Cocker Spaniels, Dachshunds, and female dogs are over-represented; may be linked to hormonal factors

Diagnosis depends on clinical presentation. For most routine cases, a rectal examination and external anal gland palpation is sufficient. For more complex or recurring problems our evaluation expands:

• Rectal examination — assesses gland consistency (soft/full = impacted; firm/painful = abscess; very hard/irregular = suspicious for tumor)
• Cytology of expressed contents — if the secretion looks purulent or bloody, a smear is examined under the microscope to confirm infection and guide antibiotic choice
• Culture and sensitivity — for cases of recurrent or non-resolving infection
• Abdominal ultrasound — for any firm or irregular anal gland mass; evaluates the sublumbar lymph nodes (medial iliac lymph nodes), which are the first site of spread for anal sac adenocarcinoma
• Serum calcium level — hypercalcemia is a paraneoplastic sign of anal sac adenocarcinoma and a prompt for tumor workup even before a mass is palpated
• CT scan — used for surgical planning in confirmed or suspected anal sac adenocarcinoma

Treatment is matched to the severity and underlying cause:

• Manual expression — external or internal expression of impacted glands by a veterinarian; often provides immediate relief; not a cure for the underlying cause
• Antibiotics and anti-inflammatories — for infected or abscessed glands; oral antibiotics based on culture results and, when necessary, surgical lavage of the abscess cavity
• Dietary modification and fiber supplementation — a high-fiber diet or added psyllium firms stools and promotes natural gland expression; very effective for dogs with chronic soft stool–related impaction
• Allergy management — investigating and treating underlying food or environmental allergies dramatically reduces anal gland problems in many dogs; may involve a hydrolyzed or novel-protein food trial
• Anal sacculectomy (anal gland removal surgery) — definitive treatment for dogs with frequent recurrence (typically 4 or more expressions per year), irreparable abscesses, or benign tumors; Dr. Schulman performs this procedure with attention to preserving the anal sphincter muscles to maintain continence
• Oncologic surgery and chemotherapy — anal sac adenocarcinoma is treated with surgical removal of the tumor and affected lymph nodes; chemotherapy and radiation are used adjunctively; prognosis depends on lymph node status at diagnosis

A dog scooting occasionally is common and often resolves with a single expression visit. A dog scooting every few weeks, or one that has developed swelling or a draining wound beside the anus, warrants a diagnostic work-up to identify the underlying driver — allergy, diet, or anatomy. Any firm, irregular, or rapidly growing mass near the anus should be evaluated promptly with ultrasound and, if indicated, fine-needle aspiration, given the possibility of anal sac adenocarcinoma. Our Calabasas team can express, evaluate, and image in the same visit. Book an appointment for relief today.