Could my cat have worms?

He's 10 months old and has had the runs since I've adopted him almost 2 months ago on and off. One week he's fine and the next it's runny or pancaky with a horrible smell that can clear a room lol he does fart a lot at times as well. I check his bum and poop and there's no sign of worms at all. We did switch his food a few times with no luck and he even gets added probiotics twice a day with no changes as well. Could he have worms if I don't see them? Or do you think it might be more of a food allergy since he eats and drinks fine and is a happy little guy!

If he's had any outdoor access at all it's quite possible that he does have worms. Your vet will be able to tell for sure. all they need is to see a stool sample. If you are going to worm him make sure you get a wormer from your vet. Don't use the cheap over-the-counter ones as they can cause severe allergic reactions.

Has he ever been checked over by a vet? There are lots of other things that can cause runny stool and bad gas so ask your vet to take a look at him, just to be on the safe side.