This morning my cat came in from outside and is acting very hyper. He was panting heavily and does not seem to be able to sit still. His skin keeps twitching and he keeps licking himself frantically, like he is trying to get rid of something. I used Frontline on him last week and I do not see any indication of fleas anywhere. He also had his annual vaccines just last week. It almost seems like something is crawling around inside of him and he's trying to get at it.
Thank you for writing in with your question and concerns about your kitty.
The most likely thing is fleas, even though he was just recently treated with Frontline. This is especially true if your are seeing him biting or licking at his rear end and tail area. The twitching skin is often from the sensation of having the fleas crawling on him. You said that you don't see any indication of fleas, but I would have to ask whether you have used a flea comb and combed him thoroughly for live fleas and flea dirt.
Flea "dirt" has a dark, dirt-like appearance that you will find on the hair when combing your cat. The fleas bite your cat, and this "dirt" is actually dried blood. When you find anything that appears to be dirt when combing a cat for fleas, you should firmly rub the dirt on a white, damp paper towel. If the "dirt" is in fact from fleas, it will create a rusty color on the paper towel, which indicates blood.
That said, if it isn't fleas, it could be that something stung him or bit him. It could also be that something got on his fur and he is trying to get it off. Ultimately, there are many possibilities, but fleas are always at the head of the list.
All the best,