Q: Hi Dr. Mitchell! I have a question, & I thought I'd ask here in case others have a similar question. We gave Duke a topical tick/flea treatment on Tuesday. This morning at 2:30 am, he was sprayed by a skunk. Two hydrogen peroxide + baking soda + dish soap sponge baths and a regular bath later, he smells much nicer. I was wondering if we need to apply another round of the tick/flea treatment now or if it soaked into his skin & we should wait until next month. I'm not entirely sure how they work. Thanks for your advice!

A: It depends on the product you use. In general, topicals work by rapidly spreading over the skin surface of most of the pet's body - where they are stored in oil glands, & then gradually release over the next 4-8 weeks along with skin oils. In general, they CAN be rinsed or washed off enough to significantly reduce how long they will last, especially if the bath/rinse (or even a swim in a pool or lake) happens within a few days of application. Soap would definitely help remove more, as would multiple rinses/baths.

Usually, when treating to remove skunk smell, we are pretty invested in getting as much smell off as possible - & that smell comes from the oily residue in the skunk’s anal glands. That’s why most helpful skunk remedies use a soap as one of the ingredients. That same soap would remove the pet’s own oils - along with your flea & tick product.

So while a Tuesday treatment would likely survive a single Sunday dunk in a lake, I’d expect that your very effective de-skunking treatment (*yawn*, at 2:30 am, yet!!!) removed a lot of your flea & tick product, too. To avoid over-dosing, I’d keep Duke out of brushy areas for the next 2 weeks and then reapply your treatment - if it was Frontline Plus. (If it was something else, I’d contact the manufacturer and ask for advice).

Here’s some specific advice from the makers of Frontline Plus, for their product only, skunks not withstanding: Bathe FIRST, and then apply the Frontline Plus.

• It is okay to bathe your pet before using FRONTLINE Plus but the coat should be completely dry prior to application.

• It is recommended not to bathe, shampoo or swim pets during the 48 hours after treatment.

• Excessive washing or swimming may potentially interfere with your flea preventative and more frequent application be required.

• Speak to your vet about appropriate shampoos to use on your pet.