Cat Rectal Discharge: Causes, Diagnosis, and Veterinary Guidance

Red or odorless rectal discharge in cats warrants prompt veterinary evaluation. Several conditions can cause this symptom, each with distinct characteristics.

Differential Diagnoses

• Anal gland impaction or abscess: Produces thick, foul-smelling secretion often tinged brown or red; associated with scooting and excessive licking.
• Colitis or diarrhea: Mucus or blood from colonic inflammation due to inflammatory bowel disease, parasites, or dietary indiscretion.
• Rectal prolapse: Protrusion of rectal mucosa; often linked to straining, diarrhea, or history of parturition.
• Trauma: Bite wounds, foreign bodies, or perineal hernia.
• Neoplasia: Adenocarcinoma or lymphoma, more common in older cats.
• Coagulopathy: Rodenticide toxicity or liver failure leading to bleeding disorders.

Diagnostic Approach

1. Physical and rectal examination to palpate glands, assess tone, and detect masses.
2. Fecal PCR and parasitology.
3. Complete blood count, chemistry panel, and coagulation profile.
4. Imaging (radiographs, ultrasound) if a mass is suspected.
5. Biopsy if neoplasia is considered.

Treatment targets the underlying cause: anal gland expression and antibiotics, deworming, anti-inflammatories, surgery, or oncology referral as appropriate.