Why has my dog suddenly started kicking his leg when scratched?

Previously my dog never kicked his legs whilst being scratched like most dogs do.

Suddenly he has started doing it anytime I scratch him and I have noticed I can scratch him anywhere, like on his back side or belly and he will kick his legs.

After research I've seen it could be related to his nerves and an evolutionary need to get rid of flies and ticks, but why has it only just started happening, he doesn't seem bothered or changed in any way other than this.

He's 6 btw.

Comments

Hi did you ever get any answers on this. I had a horrible experience with a Rover sitter and now BOTH of my dogs are kicking their legs at the SLIGHTEST of pets or scratches. They were never like this before! I’m extremely concerned. Would love to hear if you ever figured this out. Thanks, Hans