The itching pet is one of the most common problems that we see. Sometimes the cause is not obvious to the owner, but yields readily to a thorough examination. For instance, we commonly find unsuspected flea populations on animals with long, dark coats. Young puppies with bad itching are most likely to have Sarcoptic mange ("Scabies"). In fact, the dermatologist say that "they have scabies until you prove it's something else: treat them for Scabies." Fortunately, this is now a simple matter. We just treat three times with Revolution at 2-week intervals (versus the old days of whole-body clipping, followed by whole-body dipping every week in something toxic and stinky).
All too often, when a cause is not readily visible, we just assume that the pet has an allergy. Of course, this is frequently the cause of itching (especially in Southeast Missouri, home of pollen, mold, insects, and agricultural chemicals — that's what brings in the tourists).
A recent article in Science News really got me thinking about the patients who don't respond to our customary treatments. Researchers have discovered nerve fibers that are specifically involved with the sensation of itching, that are not part of the pain sensation system, and that are not involved with histamine-mediated itching (allergic itching). The whole article is really interesting. This type of itching doesn't really respond to antihistamines or cortisone.
In the past, I have prescribed Relief Spray for some itching patients. This product contains a moisturizer and and pramoxine, a local anesthetic. I have felt like just trying to numb the nerve endings temporarily was a bit of a cop-out: symptomatic treatment without understanding the underlying cause. After reading this article, I think I may have been doing the best that could be done for some of these patients.
It certainly gives me one more thing to think about with these itchy patients.
My favorite “mystery” cause of itching in pets has been the food allergy. When I have had itchy pets that did not have an easily identified cause on exam, and have not responded well to antihistamines, I have learned to give a 4-6 week trial of the prescription allergy food. For some of the itchy pets, this has been quite helpful.
Sheila,
There are lots of undiagnosed food allergy patients out there, primarily due to the logistical problem of dietary elimination trials. When it can take as long as twelve weeks to show results (though, thankfully, often not as long), and you can’t eat ANYTHING ELSE, and you have a multiple pet household, lots of folks just can’t make the effort needed to get it done.
After a year of trying, we’ve finally stopped our dog’s hotspots (and itching) by putting him on a rice, vegetables and raw chicken frame diet. It sucks that I have to cook for him, but it has been a huge relief for his health – doesn’t sound like diet is the problem with itching nerve fibres tho! Nasty 🙂
This is fascinating, I’m doing my internship right now and will be sure bring it up with the doctors. Thanks for the tip, cant wait to read the article!