Rabbit respitory distress - due to allergies?

Question
My rabbit has been rasping on and off since Feb.  Have taken him to the emerg vet 5x and regular vet 2x.  Xrays init. showed 75% fluid in lungs.  Baytril seemed effective, and then he was off of it feeling normal for a week.  Then resiritory distress resumed.  Tried baytril again, did not help.  Tried a different antibiotic, then my reg. vet took him off.  He had a shot of penicyllin.  He had a steroid injection which saved his life once.  Yesterday he almost died again, if not for my bf staying up all night taking him into the hot showered bathroom to wake him up (embolization).  We rushed him to the emerg. vet and took add'l xrays.  Showed possible "nodules", they said could be cancer.  (he is 3y.o.) Once he stabilized w/O2 therapy, we then took him to Dr. Myer in Grafton MA.  He had a nebulizer last night and I just got a call from the vet intern this morning.  He is back to perfectly normal.  She seems to think it must be allergies.  She looked at yesterday's xrays and didn't seem to think the nodules were cancer.  She is taking more xrays today, also of his skull to look at mucus membranes.   Is there a bronchial dilator medicine I should ask for if his new xrays come out negative?  It must be allergies, I think I have to replace the carpet where he lives as there had been some perfumes sprayed there.  Sorry for the short/long story let me know if you need me to elaborate on anything.
I will be hearing back from the vet in Grafton today, and dont' want to take him home if he's just going to cycle back into respitory distress, despite the improvements he always seems to make when we do have to take him to the vet.

Answer
Dear Theresa,

This really does sound strange, that he has the signs when he's at home, but then is fine at the vet's office.

In most cases, I'd suspect chronic pneumonia, and if this is the problem then the only way we've had success in treating it is with zeniquin (marbofloxacin) coupled with both *injectible* amikacin and nebulizer containing amikacin twice a day for 10 minute treatments.  If you need a nebulizer "recipe," then please let me know. But I'm guessing your vet also has one (generally it's sterile saline (carrier), amikacin (antibiotic), aminophylline (bronchodilator), and Mucomyst/acetylcysteine (mucolytic)).

I would recommend that you ask your vet for a prescription for a nebulizer.  They usually cost about $150, but if your bunny has an episode it could save his life if your vet isn't available.  The vet will have to show you how to mix the "cocktail" for the nebulizer chamber, and perhaps sell you a rabbit-appropriate mask (these are also available online at vet supply outlets), but it really could be worthwhile.  If he has severe respiratory distress, then it might also be worthwhile to ask about having an oxygen tank on hand (or buying an oxygen concentrator) online to help him when he's having an episode.

Intermittent antibiotics can be worse than none at all, since a low or occasional dose can select for resistance in the bacterial population.  Please ask the vet about combining the zeniquin and amikacin for a ten day course, and then continuing the zeniquin after that for another two weeks.  It can sometimes take a *very* long time to knock back respiratory pathogens, and they tend to recur if the bunny is immunosuppressed for any reason.

Allergies are possible, I suppose.  But they really are pretty uncommon in rabbits, and would be extremely difficult to confidently diagnose and treat.  

I hope this will help get you started on the road to his recovery.