This is a specific conversation about Flea and tick prevention — what works — ask about yours and get one honest answer for your exact situation.
inparticular.ai
An elderly dog with a compromised immune system needs flea control that works reliably without putting extra strain on their body — strong oral isoxazolines or high-dose spot-ons can be more than a senior dog needs. The most effective prevention depends on size, local tick exposure, and how robust they currently are. What's your Norwich Terrier's current weight, are you in an area with ticks as well as fleas, and has your vet flagged any specific sensitivities or conditions alongside the immune changes?
She's about 5.5kg, we're in rural Suffolk so ticks are definitely a concern too. The vet mentioned her immune system is just generally slower to respond now — no specific conditions, but they said to be cautious with harsh chemicals. She's never had a bad reaction to anything before.
inparticular.ai
That's really helpful. Rural Suffolk with ticks means you need something that covers both — and at 5.5kg she's right in the small-dog range. Given her age and the vet's caution about harsh chemicals, I'd steer away from monthly oral treatments like NexGard or Bravecto. They're very effective but they're systemic, meaning they circulate through her bloodstream, which is more load on an older immune system. A collar is a better fit here.
I've heard mixed things about collars — are they actually effective for ticks, or is that more of a flea thing?
inparticular.ai
The Seresto collar — specifically the small dog version for dogs up to 8kg — is genuinely one of the best-evidenced options for both fleas and ticks. It works by releasing two active ingredients, imidacloprid and flumethrin, in very low concentrations continuously over the skin and coat rather than entering the bloodstream in meaningful amounts. That's the key difference for an older dog: it's doing its work locally rather than systemically. Studies show it maintains effective tick repellency and kill for up to eight months. For a dog like yours — small, elderly, rural location — it's the recommendation I'd land on.
Eight months sounds good. Is it safe if she occasionally gets wet or goes swimming?
inparticular.ai
Yes, it's water-resistant. Swimming or bathing reduces the active period slightly — Bayer's data suggests it drops from eight months to about five to seven months with regular water exposure — but for a typical dog who gets wet occasionally it holds up well. Just don't scrub the collar area with shampoo when bathing her. The Seresto small dog collar is widely available on Amazon UK and usually costs around £35 to £40 for the eight-month collar. Given you'd otherwise be buying monthly spot-ons, it works out cheaper too.
That makes sense. Should I tell the vet I'm switching to this, or is it fine to just go ahead?
inparticular.ai
Worth a quick mention at her next check-up, but you don't need sign-off to use it — it's an over-the-counter product. Just let them know what you've moved to so it's on her record. One practical tip: when you fit the Seresto, leave a two-finger gap for comfort, and check the skin under the collar weekly for the first month to make sure she's not showing any localised irritation, which is rare but worth watching for in older dogs.
