June 06, 2003
Friday

Your pet's begun to itch. You know this because he's keeping you up at night with his scratching. You, as a devoted, dedicated, concerned pet owner, are paying close attention to the severity of the itching and where he's scratching. You're being careful to make sure that a secondary bacterial or yeast infection isn't clouding the diagnostic picture.

So let's talk about what you're seeing.

Your furry buddy, let's call him Cosmo, just for fun. On a scale of 1 to 10, with one being hardly ever, and 10 being scratching always, Cosmo is an eight, He scratches at all hours of the day and night, waking from a deep sleep to dig at himself, chewing his hair to a stubble, stopping in the middle of a play session to chew, chew, chew at himself.

This is pretty intense stuff, it's really bugging him, and it's really bugging you. It's about to become a serious problem, as the skin under the chewed off hairs is getting red and irritated looking.

Cosmo is a nine year old Black Lab, and he has never had any problem like this before. You're at your wits' end, willing to try anything, which is why you're reading this.

Where is Cosmo itching?

This one's important. But you've been watching carefully. When Cosmo dives for a good digging session, it's almost always aimed at the base of the tail area, sometimes under the tail, or the back of the hind legs, but it's almost always somewhere in the tail region.

So what, you ask?

Well, this is one of the first clues that a vet will use to start sifting through the evidence. The three most common causes of pruritus - itching in vet speak - are, in rapidly decreasing order of prevalence, flea allergies, atopy - inhaled allergies in vet speak - and food allergies, with food allergies being not particularly common one at all.

But flea allergies are incredibly common, and need to be cleared out of the picture as a possibility, since animals with atopy, or food allergies will often be allergic to fleas as well. In fact, it's a strong probability that it was a flea bite that put poor Cosmo over the edge into crazy itching.

Picture an animal's immune system as an ever-vigilant force, constantly patrolling the body's perimeter, searching for invaders. In an animal with allergies, the immune system is over-vigilant, identifying as invaders, substances that normal animals would ignore. In humans, clinical signs of allergies generally center around the respiratory tract, sniffling, runny eyes, sneezing, and coughing. Fun stuff.

In animals, however, clinical signs seem to be centered around the skin, resulting in itching Animals with allergies are often having subclinical allergic reactions to various substances, unbeknownst to us. But when a certain threshold of allergies has been reached, clinical signs emerge. I call it the 'Itching Threshold'.

Fleas are often the inciting factor in crossing the 'Itching Threshold', especially in dogs. But it's not the fleas that are the problem. It's their saliva. Some cats, for instance, are amazingly tolerant of fleas, showing no signs of the infestation, while they're crawling with the little buggers. On the other hand, some animals will be going crazy itching, with not a flea to be seen.

So the first thing I do when someone comes to me with an itching animal, is to institute a thorough plan of flea control, just to be sure that's not what we're dealing with.

Next week: Fleas and their control

 
franimaldoc@sitnews.org

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