Bumps on kittens ears, need help

I could use some advice or idea's ASAP. I've got a lot of kittens, 10 weeks old, just about ready to go to their new homes. It seemed to have started when I purchased a cat tree from Pet Smart. There were about 20 cat trees, near the ceiling in Pet Smart. A lady had to bring it down with a ladder. It was dusty on top. I got home & vaccumed it off. The kittens absolutely love it.
24 hours later, a client was picking out a kitten. Which she was going to pick up in a month or so. The kitten was sitting on the cat tree, I noticed it had what appeared to be one bite mark in the middle of it's ear. I pointed that out to the lady, saying it looked like the kitten had been bitten by it's mother or another kitten. 2 days later the kitten had bumps with scabs on them at the base of the ear on top of the ear. A litter mate also had bumps on his ear. I called the vet. I still thought the mother was biting the ears, as she is persistant when weaning her kittens. Another mother was chaseing kittens down, grabbing them for grooming. We decided to separate the queens from their 10 week old kittens.
2 more days went by and a 3rd kitten in the same litter now had bumpy scabs on the base of his ears. I took the whole litter in, & had skin scrappings down on each one. All were Negative. Nothing showed up on the microscope. Their ears were clean inside. The ultrviolet light was used on each kitten, to check for ringworm. That was also Negative. Nothing. A culture was done & taken to a lab.
The culture is going to take up to 2 weeks, if it's negative. The vet said, if it shows something, she might know in 5 days. The following day, 2 more kittens have tiny bumps on the base of their ears. One had them along the outer edge of his ear. The first kitten, who started with the one bite, 5 days later has what I would call, the appearance of moth bitten ears. No redness. No swelling. An occasional itch. There are no bumps, no scabs, and no hair lose anywhere else on the kittens.
I'm desparate. Does anyone have any idea's? What bug could it be? Is it possible to do 3 skin scrapings & find nothing?? What kind of fungus could it be?? Would fungus jump from kitten to kitten & attack only the ears?? Any idea's on what I could bathe these kitties in ? The vet did suggest a flea powder or some such thing, in hopes that if it is a bug, the powder would take care of it. I had some Revolution on hand, which is safe for 10 wk old kittens, so I have put that on them. I've done the wash everything in bleach water. I took the Pet Smart cat tree away from them, and sprayed it with premise spray. If it would turn out to be a fungus, I guess I'll need to burn all cat beds, cat trees, whatever. I have a notion that the fungal culture may turn up nothing also. I don't know how to fight or fix an unknown problem. If I don't do something soon, all my gorgeous kittens are going to have terrible looking ears. I've got another appointment in the morning for what was suppose to be well kitten vet exams. I don't think the vet will have any more ideas for me.

Scratching around the ears can cause scabbing. I would imagine there is some kind of allergy. It could be a reaction to the new wet/dry food. Usually allergies show up as itchy ears. Make sure whatever food you are giving them has no corn as that is a major allergen that some cats may react to more extremely than others. Otherwise...is there something used in cleaning or perfume/scents (on handlers hands) or something that could be causing an allergy?

Thats really the only thing I can think of. Other than fleas. Fleas obviously can cause lots of itchiness.

I mean you've tested for parasites so that narrows things down a bit.

Good luck with the kitties though .

I remembered reading something in a book about this and it had all kinds of things including mange mites.. but if the vet didn't find anything... how strange. the vet should find what ever the problem is..

Are the kittens claws trimmed? Have you changed your cat litter? I would bathe them in a medicated shampoo just in case. See if you can get one that is also antifungle. Ringworm often starts on the ears and then hits other parts of the body.

There ia also an atypical ringworm fungus that isn't showing up with the black light. You do not have to burn everything as the heat from the dryer will kill all the spoors. 1/4 cup bleach to a gallon of water will kill the spoors on your floors, walls, and counters.

Use a vacuum with a hepa filter on all furniture and spray with the bleach water (after checking that it will not affect the color) and wipe to get it coated evenly.

I was back at the vet today, with my other kittens. 3 of which now have this stuff starting on the outer edges of their ears. Clinically the vet is inclined to think it is a mite, probably scabies, also known as nortoedric mange or sarcoptic mites. It's not inflamed & doesn't have the appearance of what she usually sees, but most people bring in a pet when it's covered with scabies, not when it's first starting.
Her book claims a scrapeing is easy in a cat to identify scabies, but she said with dogs, frequently, you don't ever find the bug. Which might explain why she couldn't find a bug. Lime sulfur dip was her suggestion, if I wanted to do something more immediately, but I should check with the company that makes Revolution, to make sure a 2nd insectiside won't cause a problem.
One website talks about Revolution controling sarcoptic mange in dogs, it hasn't been approved for cats, probably because of the expensive process to gain FDA approval. The site also said it seems to be effective.
I put the Revolution on them on Mon. Today on Wed. only one kitten has itched her ear. None of the first 3 affected have been itching at all today. I'm going to wait another day or so, and see if it spreads to any more kittens. If it doesn't, I may not need to do anything else.
Another dip mentioned as a one time treatment, is Malathion. That was taken off the market for pets I believe, but can still be purchased for plants/trees, etc. I've got some of that on hand, as I used to dip dogs with it. Smelly stuff,, but worked extremely well. My vet didn't know it had been pulled from the market. Lime sulfa is supposed to stain, so not sure I want to put that on my kittens, if I don't have to.
She also read that injectable Ivermectin works, but that it isn't approved for cats. Injectable Ivermectin, could be difficult to dose a small animal. I don't know if I want to risk that.

I've done lyme dips with 2 kittens before. Its not fun but certainly worth it if you think this is remotely parasitic. You have to put a vaseline type goop in the cats eyes otherwise it will burn..

Let me warn you if you think bathing a cat is hard...try putting them in sulfur. Teh poor things will scream their heads off and it sounds like your trying to murder them. Its horrendous. Not to mention it will stink horribly.

But this is really the best solution that is available. I've used another medicated shampoo and it did nothing. I say don't risk it and go wtih the sulfur dip. Just be prepared....and plan on opening the windows.

They used to use Malathion to kill nasty insects and it is dangerous to pets and human beings!!!!!!!! Remember anything we put on our skin absorbs in our bloodstream!!!!! Our skin breathes and I am sure it would be the same for cats!!

I used Malathion for 10 years or more as a dip for dogs. Never had a flea or tick on them. Dipped them only once in the spring, it was good for the whole summer. It is sold to be used on fruits, vegtables, trees, shrubs, etc. It was pulled from the market for use on animals. I'm assumeing it got into food by being used on animals for market. I'm not sure why it was outlawed for animals. It's still labeled for vegtable/fruit use.
I actually quit using a dip, because of the work involved. Dipping dogs who disliked the stuff, having to keep them somewhere to dry so they wouldn't roll on the ground. I've never put it on a cat, but I still have the product label for domestic pets.