Stubborn Cheyletiellosis

Question
I'm a vet and I'm currently treating a young female rabbit for cheyletiellosis. The rabbit presented with copious dandruff and seborrheic lesions on it's neck and along it's dorsum. The rabbit was only mildly pruritic. No other health problems have been identified. My first-line treatment was topical ivermectin but this only improved the rabbit's condition slightly. I have since administered three subcutaneous injections of ivermectin at two week intervals. The rabbit's condition has improved dramatically and only a small amount of dandruff and seborrhoea remains. The lesions appeared to clear up in a caudal direction from the head to the tail. The rabbit is perfectly happy and no longer pruritic. However, the condition is stubbornly refusing to resolve completely and I am unwilling to continue giving ivermectin injections without seeking the advice of a rabbit specialist. If you could provide any advice on treating cheyletiella it would be most appreciated. Thank you.

Answer
Dear Heather,

We have had much better success treating Cheyletiella with selamectin (Stronghold/Revolution) than with ivermectin.  Selamectin has a longer "hang time" than ivermectin, and so will more likely be ingested by the fur mites constantly, including newly hatched mites.

We have noticed, though, that it's usually rabbits who are otherwise compromised who show signs of Cheyletiella infestation.  So it might be a good idea to do a complete wellness check on this little gal to be sure there is not some underlying health problem that is weakening her immune system and allowing the mite population to grow to pathological levels.

I hope this helps.

Dana