Visiting Veterinarian : Sounds gross
"Someone on the phone wants to know if she can catch ear mites from her cat," my secretary announced. That was a new one. I've been asked about the zoonotic potential of everything from ringworm to Lyme disease, but no one has ever asked about ear mites before. (A zoonotic disease is one that can be transmitted from animals to people.) I paused, wondering what nasty symptoms the caller might be experiencing to elicit this query, or if it was just idle curiosity.
Otodectes cynotis. From Latin for "biter of the ear." Ear mites are members of the Arachnida class, which includes spiders, scorpions, and ticks, as well as mites. Although some people claim to be able to see them with the naked eye, this ability has always eluded me, even in my pre-bifocal days, but I love to scoop a hunk of classic "coffee grounds" debris from the ear of some head-shaking kitty, mix it with a drop of oil on a slide, pop it on the microscope, and say "Wanna see why Mighty Joe is scratching?" "Sure," replies the innocent owner, who ambles over to the scope, then lets out a gasp or an "eeewwwww" as she gazes down at dozens of active, creepy, six-legged critters swimming around on the slide.
The ear mite has an unusual lifecycle. Eggs hatch into larvae that feed on earwax and skin oils. After a week, these molt and become protonymphs. They keep eating, then molt again into deutonymphs. Here's where it gets strange. The deutonymph, which as yet is neither male nor female, mates with an adult male mite. It is only after mating that it goes through a final molt, which determines its gender. If it turns out female, then she is already pregnant with fertilized eggs from that mating. If it turns out male, nothing happens, and it may go on to breed with other deutonymphs. The entire lifecycle takes three weeks. Otodectes mites do not burrow under the skin but are still extremely irritating, causing inflammation and predisposition to secondary bacterial and yeast infections. Most mites stay inside the ears, but may occasionally spread to the head or face.
The majority of all feline ear infections are caused by mites, which are passed from infected mother to kittens or between adult cats in the course of cuddling, grooming, or close cohabitation. Affected ears are filled with characteristically dark, dry, granular debris and are usually intensely itchy.
Dogs are a different story. Owners often erroneously assume their pups' ear problems are caused by mites, but in fact, ear mites account for very few of canine otitis cases. The majority of doggy ear infections are caused by bacteria and/or yeast and require an entirely different treatment than a mite infection. That's why that "ear mite remedy" you got at the pet store isn't solving Fido's problem.
Effective mite treatment requires thorough ear cleaning, followed by appropriate medication for all exposed pets. If it really is mites, that pet store remedy will probably work - but only if applied daily for a month. (Since most OTC products do not kill the eggs, treatment through a complete lifecycle is needed to truly knock out the infestation.) Then there is the prescription medication Tresaderm, which veterinarians have dispensed for decades. A 10-day course is usually sufficient to eliminate mites and has the added advantages of containing an anti-inflammatory and treating secondary bacterial and yeast infections. The down side is that you have to refrigerate it, and Mighty Joe may find those ice-cold drops mighty annoying. Ten days is easier than 30, but still a major hassle for pet owners, leading to poor compliance.