Why do Pets Twitch When Their Skin is Touched?
Cat lovers take note: this entry does not just cover dogs!
My 3-year-old Rottie/Shepherd mix seems to be very touch sensitive. He quivers when he’s touched on his flanks and back. It seems to be in surprise rather than pain, as if he’s not expecting to be touched, though he doesn’t react similarly to touch elsewhere and he doesn’t object to it – it just seems to surprise him. He doesn’t whine or otherwise vocalize. He sees his vet regularly and is in good health.
Margaret
South Austin, TX
Trembling and quivering are very common in pets. Almost anything that can make a human tremble or quiver can make a pet do so as well. There are some exceptions. For instance, I have yet to see a dog or cat tremble upon hearing his favorite piece of music.
Certain medical conditions and metabolic irregularities can lead to trembling, quivering, or increased sensitivity to touch. But based upon your description I doubt that your dog has a medical problem.
Every person has experienced a chill go down the spine when his or her skin was touched in just the right way. That is what I suspect is happening in your dog.
The most sensitive area on many pets is along the back, especially near the tail. This area appears to have highly sensitized nerve endings. Many cats especially are prone to twitching their skin when this area is stroked. Some cats are so sensitive in this area that they engage in compulsive grooming behavior when scratched near the base of the tail.
Flea allergies sometimes exacerbate the sensitivity of the skin and may cause increased twitching when pets are handled. But I am guessing that fleas aren’t playing a role in your dog’s behavior. As long as your dog doesn’t seem distressed when you pet him, I see nothing to worry about.
Photo: there are no reports of excessive skin sensitivity in Sophie.
You have questions. 
Every single time I lightly touch my 7-year-old male cat anywhere on his lower back, he twitches where I touched him. I can do it repeatedly and it doesn’t bother him – I think he kind of likes it! He’s healthy, happy, and it’s humerous; I’m certain it’s nothing to worry about.
My Shep-Rottie does the same thing!
Our cats beg for “tail scratchies”. They are particular, however, about who does this. Just family members only!