Hi. My cat Chloe has been spending a lot of time at the vets recently due to blocked anal glands (now removed). Scooting on the carpet and over-grooming were two of the visible signs. On her most recent visit, for a post-op check-up and annual booster injection, the vet commented on the over-grooming and inspected her skin. He came to the conclusion she has dermatitis, possibly as a result of being allergic to flea bites. She also has the 6 monthly program flea injection. He explained it does not kill fleas just makes them sterile. I originally stopped using the spot-on because it seemed to really sting her and i noticed a sore patch on her skin afterwards. So I now have a large tin of flea spray to kill any fleas still lingering in the house. However I am now in two minds whether to return to the spot-on, even though she hates it so much and runs a mile. I will wait to see if the can of flea killer does its job in which case I will continue with the 6 monthly flea injection. Swings and roundabouts, I think.