Cyclosporine treatment of anal furunculosis in 26 dogs.

Objectives: To evaluate the effect of cyclosporine on anal furunculosis lesions in 26 dogs. Methods: Lesions were graded as mild in 11 dogs, moderate in eight and severe in seven. Each dog was treated with approximately 4 mg/kg cyclosporine orally every 12 hours until the lesions resolved or showed no further improvement. Residual lesions were resected surgically. Results: Eighteen dogs (69 per cent) experienced complete resolution, seven (27 per cent) improved but had residual lesions and one (4 per cent) showed no improvement. The mean duration of treatment until resolution or no further improvement was 8.8 weeks (range four to 24 weeks). Nine dogs (35 per cent) experienced recurrence. Six were from the group that had shown complete resolution and three were from the group that had surgery. Fifteen dogs (58 per cent) developed side effects to cyclosporine, although none required treatment to be discontinued. Mean duration of follow-up was 6.8 months (range one to 20 months). Clinical Significance: Cyclosporine was effective at resolving or reducing anal furunculosis lesions in 25 of 26 dogs (96 per cent). However, residual or recurrent lesions in a potential problem, and surgical resection or long-term cyclosporine treatment may be necessary in some dogs.