I remember my kitty had gottent sick and even had poop in his blood and was throwing up, I was giving him the best cat foods Ames/wet for everything and he never went outside,(only for short walks and a little air, I kept a cat leash on him) I gave him stuff for hairballs, clipped his nails, I did more for that cat than for myself and he would still get sick. because he loved chewing plastic wrapping (from store brought items, I actually had walked up on him doing it and it was a tug of war, I don't know how long he had been doingit but apparently it affected his stomach. He was throwing uo alot and wasnt eating or running around like he normally would do, so I made him chicken broth by boiling some fresh chicken breast( I didn't put a lot of water in it ) for a few days and then I gave him chicken broth with bits of chicken, cutting it in small pieces, I put a little aloe vera juice in his water for a while and the bleeding stopped) and he got better,I never treated him with any antifungals I didn't know about that then, I didn't have a computer at the time. But I stopped giving him wet cat food because sitting out flies would get on it (the uneaten portions ) and they carry diseases) also the food would spoil the next day so I switched to dry but would occassionally give him sardines or tuna as a treat. But if I gave him wet food it would be very, small cans, I couldn't afford the Vet.
But if you are giving them wet cat food try the Ames dry they have good ones,there is another cat food I used to give my kitty it was Pureana indoor Green Cat Food,(dry also) it has all the greens from plants and vitamins, Sience Diet is also good/Dry. They may take a little getting used too but trust me they will eat it. I used to order all that stuff from a place ran by 2 Veternerans. they have everything from food to meds. It's possible they probably have parasites because they have stuff for worms too, that's why people shouldn't let their dogs lick their mouths because they can make them sick too, cats lick themselves. I'll look it up for you, but they do have antifungals for cats too, here: http://www.bullwrinkle.com/ShoppingPages/conofite-lotion-cream-spray.htm also: http://www.1800petmeds.com/Antifungal-Antiprotozoal-cat73.html they have everything you need for Kitties and they don't charge a lot either.
Of couse you will have the mix it with the food unless your Kitties comply with it, I know in the past mine didn't when it came to giving him meds he was smart as a whip. I meant to tell you Virgin coconut oil is also good for skin conditions too, I use it everyday.
The other place I was talking about that is own by the two Vets that have food, supplies and meds for animals is: http://www.drsfostersmith.com/pet-meds/pr/c/9547 Their prices are pretty good also.