biting during grooming near the tail

My cat keeps biting the back of my hand when I’m trying to brush his fur, especially around the tail area. He seems relaxed until I get to that spot, then he snaps.

I’ve already documented the history and what we tried at the vet in Willow's allergy update and vet notes. The vet checked for fleas and found none, but Willow has a known allergy profile. I measured the time between brushing sessions and the biting incidents; it correlates with the days after his last bath, which was 14 days ago.

Short answer. Pain. If it's the tail base, check for hairballs or mats near the anus. Puff gets hairball issues and I see Dealing with Puff's hairball issues for what I use. If it's not mats, it's skin irritation. Rio had fleas but that's in Rio's flea history and current treatment so probably not that.

Walter, have you considered that the tail area is sensitive for many cats due to proximity to the spine? When I handled Ollie's tail during his Managing Ollie's diabetes at home checks, he would tolerate it only if I moved slowly. Mabel is older, so I am extra careful with her, as noted in Mabel's kidney stage 1 care plan.

I wonder if Willow is reacting to pressure rather than pain. Try a softer brush or just your fingers to see if the reaction persists.

This reminds me of when Kiki was first coming home. She had anxiety issues, detailed in Kiki's anxiety signs and triggers, and would bite if I touched her near her tail. It wasn't pain, it was overstimulation. Koda, who is in Integrating Koda with Kiki, is much calmer, but he still pulls away if I brush too fast.

Is it possible Willow is just sensitive to the texture of the brush on that specific part?

@kristen.cook I checked the texture variable. I swapped the brush for a silicone pad. The biting frequency dropped by 40% but did not stop. The tail base is still the trigger point. @dreed I checked for mats. None found. The fur is clean. @joan.webb I tried slow movements. No change.

If it's not mats or texture. Could be old injury. Rio had a tail issue before. Check for swelling. If swollen, vet today. If not, try desensitization. Touch tail, stop before bite. Repeat. Takes time.

Walter, your data is very helpful. Since the silicone pad reduced the issue but didn't solve it, and mats are ruled out, I think we are looking at a neurological sensitivity or a mild arthritis issue, given Willow is six. It is not too old for early joint issues. I would suggest a visit to a specialist if the desensitization method @dreed suggests does not yield results in two weeks.