A practical parasite plan for pruritic patients (Sponsored by Pfizer Animal Health)
Therefore, veterinarians have two goals for pruritic patients: manage primary disease and eliminate secondary infections. This article focuses on how parasites and parasite hypersensitivity cause pruritus and provides the busy practitioner with tips to help improve diagnosis, treatment, and client interactions.
1. Perform parasite treatment trials to rule out occult parasitism.
2. Prescribe safe and effective miticides for parasite treatment trials.
Selamectin administered every two weeks for three treatments is a common protocol for Sarcoptes and Otodectes in dogs and cats. Off-label use of ivermectin at 200 to 600 ug/kg once weekly for four weeks is also widely used to treat canine Sarcoptes. Certain breeds commonly carry a gene mutation that increases the risk of neurotoxicity from ivermectin at this dosage. However, any individual dog of any breed can be ivermectin sensitive. Since consequences can be dire, all patients on high-dose ivermectin should be either tested for the multidrugresistance (MDR) 1 mutant gene or given lower doses first. If owners observe signs of neurotoxicity (ataxia, mydriasis, tremors, obtundation) at lower doses, discontinue therapy. Rather than risking a toxic event or using valuable consultation time discussing ivermectin toxicosis, the author recommends avoiding routine use of ivermectin for parasite treatment trials when there are safe, effective, and FDA approved alternatives readily available.
3. Relay to clients that comprehensive flea control is essential for all pruritic patients. Focus on prevention rather than treatment when talking to owners who may be reluctant to implement flea control.
Veterinarians have many products available. Selection depends on each specific situation. For example, in atopic patients, if frequent bathing is recommended to manage secondary skin infections or reduce absorption of environmental allergens across the skin, use systemic flea products that cannot be washed off. Examples include selamectin, spinosad, and nitenpyram. Because of a short duration of action, nitenpyram should be repeated as often as one time daily or administered in combination with other products.
4. Perceived treatment failure is more likely due to newly emerged fleas than from resistance to the product.
To obtain the ideal of rapid kill, long duration, systemic distribution, and miticidal activity, combining multiple products, such as selemectin for safe and effective broad mite and flea management with dinotefuran, nitenpyram, or spinosad for rapid flea kill can be useful in certain circumstances. Consult the manufacturer for safety and compatibility with other products if combination therapy is necessary. ??
Table 1. Phrases to use with clients
Here are some examples of phrases to use with clients to emphasize the importance of prevention:
"Fleas probably aren't Skipper's problem; however, fleas still aren't his friend. His itch is severe already, imagine how much worse it would be if he got fleas too."
"We are doing this to figure out why Skipper is itchy. Getting flea bites in the middle of the food trial would really confuse the situation. Let's make sure that can't happen."
"Let's control what we can so we can narrow down the possibilities of what is making Skipper itch. We can't control pollen, but we can control fleas!"
"Usually people are bitten by newly hatched fleas. By the time you get bit, you have an infestation. It's much easier to prevent fleas now than to eliminate fleas later."