Sarcoptes scabiei is a highly contagious parasitic skin disease that causes intense pruritus.

Diagnosis via skin scrapings may be difficult, and many diagnoses are made through therapeutic response. This study describes the use of pyriprole, a spot-on flea and tick control formulation, for the treatment of canine scabies. Twenty dogs with naturally occurring scabies and clinical assessments/mite counts performed 2 days prior to treatment were included in the study. Dogs were housed in individual pens to eliminate direct contact between them, and mite counts and examinations were used to divide them into 2 relatively similar groups. Dogs were treated at days 0 and 30 with either 12.5% spot-on pyriprole (group 1) or 10% imidacloprid with 2.5% moxidectin (Advocate, (group 2). Posttreatment clinical evaluations and mite counts performed at days 28, 60, and 90 recorded the presence or absence of mite/eggs, papules, crusts, and estimated hair regrowth. Skin scrapings were positive for mites in only 1 dog at a single time point posttreatment (pyriprole group, day 60), and live mites were not detected in any other dogs at any other remaining time points.There was 100% resolution of mites in both treatment groups by day 90. Approximately 90% of hair had grown in all dogs by day 90, and all 20 dogs had 100% resolution of mite infestations. In addition, all skin lesions had resolved except for crusts consistent with healing lesions in 2 dogs from the pyriprole group. Study supported by: Novartis Animal Health

Commentary: Pyriprole (Prac-Tic, is not yet available in the U.S. It works by interacting with ligand-gated chloride channels blocking pre- and postsynaptic transfer of chloride ions across cell membranes. In this study, both Advocate (Advantage Multi) and pyriprole were both efficacious when administered at days 0 and 30 in dogs with known scabies infestations. Complete resolution of papules and crusts took almost 90 days; this may be secondary to scabies or secondary bacterial infections that were untreated. Study results suggest that dogs at increased risk for scabies may benefit from routine use of a flea control treatment (pyriprole or imidacloprid/moxidectin). This “at risk” population would include any dog with other chronic skin diseases with pruritus as a clinical sign or dogs that maintain contact with other dogs as part of their lifestyle.—Karen A. Moriello, DVM, Diplomate ACVD

Efficacy of a spot-on formulation of pyriprole on dogs infested with Sarcoptes scabiei. Fourie JJ, Horak IG, de la Puente Redondo V. VET REC 167:442-445, 2010.