Bulges at Base of Ears

Question

Leroy with Bulges  

Leroy without Bulges   Hi Dr. Dana,
  Quite a long while back I asked about the bulges at the base of my mini lop, Leroy's, ears....I did a number of things to address them including Baytril (oral and otic) and Pen G injections. The thing that brought about the best result was Zymox (hydro cortisone free).

  One of the first things that was done to him was a needle aspiration of one of the bulges that yielded nothing but a tiny bit of blood....no pus or infection.

  With that absence of pus or infection, coupled with how quickly the bulges (when they return, on occasion)go back down with the application of the Zymox, I'm wondering if those bulges are merely trapped air?! Another thing I noticed was that during the Zymox treatment, when I would rub Leroy's ears, I would hear a tiny crackling coming from them....like massaging them was helping the air to escape.

   I've been told that rabbits have very straight Eustachian tubes...could that physiology coupled with my Leroy's tendency to get funky and yeasty ears cause air to get trapped in a spot at the base of his ears?

   I'm attaching a photo of him with and without the bulges...perhaps you remember his case....  

  thanks and yerz trooly,
      Ellen

Answer
Dear Ellen

If the Zymox helps, then this is very likely an infection.  Aspiration of rabbit pus will not be fruitful, as it's hard as cheese and will not aspirate (rabbits lack the enzyme that liquefies pus).

When you lift the ear and look inside, is there any sign of inflammation, and can the vet see signs of pus behind the ear drum?  In lops, this is a common problem, as the abnormal ear position reduces air flow and provides a moist, warm environment for opportunistic bacteria to set up shop and cause problems like this.

You can continue with the Zymox for life.  But if this is really chronic and causing him pain, then you might try to find a very rabbit experienced vet and ask about marsupializing the ear. This surgery involves incising the base of the ear to widen the ear opening to allow more air flow and easier flushing.  You can find a description here:

http://www.medirabbit.com/EN/Surgery/Ear/ear_surgery.pdf

The pictures are graphic, but the bunny came out fine.  

I hope this helps.

Dana