Your Pet's Best Friend

Deep Pyoderma

The June issue of Veterinary Forum magazine came, and was sitting on my desk (on top of the pile of journals and stuff).  The cover illustration is the teaser for an article about treating pyoderma (Translation: Pus in the skin, or skin infections).  It was really weird to have Star come in looking like she'd gone to the beauty-shop with her fashion magazine, saying "I want to look like this."  Life imitates art.

The article is about treating deep skin infections, primarily those caused by surface skin bacteria that have gone crazy.  Everybody has staph bacteria on their skin, but unless you scratch it open, or your immune system is lying down on the job, they just stay on the outside.  When they go deep, it can take months to clear the infection.

Even if you pick an antibiotic to which the germ is sensitive (the magic bullet), it takes about three weeks to grow a new layer of skin.  You won't clear these deep lesions with one week of treatment.  If the problem is really severe, the patient will need antibiotics until looking good, and for 3 weeks afterward (or longer).  Topical therapy with medicated shampoos and rinses are often required.

You also need to look for underlying causes.  There is always a reason for this (though you may have trouble figuring out what that reason is).   You check a skin scraping for mange mites, and make an impression smear cytology (smear the goo out and stain it, look at it under the microscope). Blood-work may reveal thyroid problems or other medical conditions that would lower the pet's resistance to infection.

A biopsy may be required to tell whether this is really an infectious process, or some other disease that the surface bacteria have simply used as an opportunity to enter.   A portion of the biopsy (tissue that you remove for analysis) can be sent to be cultured to find out what germs are growing there, and what medications are best to treat them.

Skin conditions can rarely be diagnosed just from their outward condition.  Star "looks just like the picture".  However, her pen-mate is developing similar lesions.  It isn't very likely that they both developed the same medical condition that allowed Staph bacteria to go crazy.  In fact, we are looking at the possibility of Blastomycosis (a bad disease).  False negative tests, multiple underlying causes, lots of possible reasons for the same outward appearance: it's why you don't find a lot of veterinary dermatologists around.

Demodex follow-up... again

  Here's Ellie Mae again, back for another check-up, two weeks later.  I had to shave a spot in order to do my follow-up skin scrapings.  She has no areas of hair loss, no scabs, no scale, no nothing except healthy-looking hair and skin.  Two skin scrapings yielded the shriveled carcass of one dead mange mite.  We're almost home.

Demodex follow-up returns

At our four weeks follow-up, Ellie Mae was a lot better.  This picture is a re-run from that last visit.  Today, at 7 weeks of treatment,  she looks almost normal from a distance.  Her skin isn't lumpy-bumpy anymore.  It's obvious that her new hair is shorter than her old hair, but that's not a problem.  She's feeling a lot better, too.

You can see a big difference here in the top view.  What you can't see is that there are still quite a few patches where the hair is thin.  Still, even in those patches, I had to do three different skin scrapings before I found one single adult mite.  Contrast that with her first visit where a single scraping produced a multitude of mites in all life stages.

Our end-point will be a combination of normal-looking skin and no mites detected, plus two more weeks of treatment.  I think we're getting there.

Demodex Follow-up

So here's a follow-up to the case of Ellie Mae.  I promised pictures and follow-up, and here we are.

The treatment of choice for dogs with demodectic mange is daily dosing with 400 to 600 mcg/kg of ivermectin.  The problem for Ellie Mae is that many Collies carry the MDR1 gene mutation, and these dogs cannot take that kind of ivermectin dose.  The low dose in Heartgard-30 is fine for them, but the humongo doses needed to treat demodex may kill dogs who carry the MDR1 gene mutation.

Not all Collies have the gene mutation, and you can test for it, so that's what we did.  While waiting for our test results, we started Ellie Mae on daily milbemyin (Interceptor - same dose daily as for monthly heartworm prevention - effective but pricey).  I had to order my DNA test kit (and now you can send blood samples, as well as cheek swabs), so I couldn't send the test off right away.  I thought that the dog would still look bad enough for my "before" picture when she came back for the test, but it was 12 days before the kit came.  After 12 days of treatment she was already dramatically improved.

Her back doesn't look bad at all at 12 days.  Her neck is still a little crusty, but her back looked worse than that on "day 1".

Day 22 - we get the bad news.  Ellie Mae DOES have the MDR1 mutation, and cannot safely take the big doses of ivermectin (inexpensive) and our best bet is to continue the oral milbemycin.

Day 29 - Here she is for a recheck and her back looks essentially normal, though she needs to grow some more hair. 

The neck is still a little crusty, but mucho improved.  The skin infection is pretty much gone. We're down to bathing the bad spots with benzoyl peroxide shampoo (SulfOxydex) and giving the oral milbemycin.

How long will she get treated?  Until she looks completely normal.  Then I'll shave a spot and do another skin scraping.  If I find mites, we'll continue treatment for two more weeks and check again.  When we can't find mites, we'll treat for two more weeks.  Then we'll call it good (and hope it is good).

How are these people affording daily Interceptor?  Well, you know what they say: it's an ill wind that blows nobody good.  A while back, we over-purchased on boxes of Interceptor single doses -- the "bulk pack".  We didn't use it before it went out of date.  So here I am with a box of expensive tablets that I can't send back, and I can't sell.  They're sure too good to throw away, though.  That's what Ellie Mae is taking.  My bad inventory management is her good fortune.

Dog with a skin problem = Do a skin scraping cytology exam

The dermatologists harp on this, and for good reason.  When a dog has a skin problem, you frequently see a very non-specific outward appearance.  If he's been scratching it, it just looks like it's been scratched a lot.  You will probably see hair loss, flaking skin, redness, crusts, scabs, maybe some pimples.  This will be the case whether he has allergies, skin infections (bacterial, yeast,or  deep fungal), mange mites, or some combination of the above.  You might also see this with auto-immune diseases, where the body's own defenses go haywire and attack the skin.  The rule is, every skin case gets a skin scraping exam.  If it's not getting better, do the skin scraping again, even if you didn't find anything last time.  There have been numerous occasions when I did the skin scraping as a formality ("because you're supposed to") and found mites that I had not suspected at all.

"Ellie May" is a Collie with demodex mites(I'll get her picture on here when she comes back for the recheck; we were a little pressed for time today, as we spent a lot of time getting a year's worth of history, and then explaining the treatment plan).  She has been having skin problems for about a year (and she's about two years old).  Roughly a third of her body is covered with scabs, and she (along with her owners) has been miserable for quite a while.

She started out with small spots of hair loss and itching and skin damage.  This was diagnosed as a "hot-spot" by her previous veterinarian. [Hot-Spot, termed "pyotraumatic dermatitis" by the dermatologists: an area of skin that rapidly develops hair loss and is red and oozing; caused by excessive scratching in susceptible individuals; only a small percentage of scratching dogs develop this type of lesion.]  I suspect that they may have performed a skin scraping when Ellie May first began to have problems, but they haven't done one in a long time.

Over the past year, she has been treated repeatedly with high doses of cortisone, topical powders, and occasional systemic antibiotics (for a week, at most).  In this year, she has progressed from a recurring small spot here and there, to a third of her body severely affected.   She looks a lot like the dog in this diagram from the Hill's Atlas of Veterinary Clinical Anatomy, only a lot worse... not so happy. Pretty unhappy, in fact.

My first skin scraping yielded a ton of mites, and all life stages, from egg to grandpa. Those microscopic bugs are severely damaging her hair follicles, resulting in lots of secondary bacterial infection, which is most of why she's so miserable.

Most dogs carry a few of these mites on their skin, but compensate for it.  Their body's defenses prevent the mites from multiplying very much, and you never see a problem.  When an adult dog develops a widespread problem, you have to wonder what went wrong.  I've sent out bloodwork to look for as many potential problems as I can, but here's what I think happened.

I think that her first veterinarian did a skin scraping and didn't find mites because her initial problem may have been related to something else.  Over the last year, she has become immunosuppressed from too much cortisone.  She may have had "normal doses" and it was just too much for her, or the doses might have been excessive.  At any rate, her immune system got slowed down, and the mites took off.

Nobody checked for mange mites again, because she didn't have them to start with.  Treatment was symptomatic and superficial and not very effective.

Today I followed the dermatologist's rule and did a skin scraping first.  I did this because IT'S A RULE, and because the dog looked awful and I didn't want to miss anything, AND, since it was my first time to see her, I didn't have tunnel-vision from previous assessments (see my last post on Diabetes).

So now we're treating her skin infection pretty intensively, and NOT giving her any cortisone, and looking for any other problems and starting to treat the mange mites themselves.  I'm optimistic that she will recover and lead a normal life.

I'll keep you posted.

Interesting Itching Information

  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.

Long-acting cortisone injections in dogs.

This is a bottle of Depo Medrol.  It is one of the more commonly used long-acting cortisone injectable products.  One of the more common uses is to give long-lasting relief from allergic itching.  Allergies are a malfunction of the body's defenses, so you give enough cortisone to suppress the body's defenses a little.

I'm not crazy about using this in dogs.  You inject a blob of this stuff into the dog's thigh muscle.  The drug begins leaching into the bloodstream.  The bigger the blob, the higher the blood level of drug.  So, when you first give it, the blood level of drug is very high.  As time goes by, the blob gets smaller and smaller, so the blood level gets lower and lower.   Eventually, the blood level gets low enough that it won't suppress the itching anymore. 

The problem is this: you never really know what the blood level actually is and how much is left.  We know that the average dose in the average dog will take 8 weeks to be totally gone, but it could take longer, maybe 12 weeks or even longer.  The problem comes in when the blood level of drug is too low to stop the itching, but there's still a significant amount of drug left on board.  The dog starts itching again, so you give him another dose.  That's the second peak on the graph.  Now you've got the new dose, plus the leftovers.  He's not itching, but you may have boosted his cortisone levels to an unsafe level. 

So, what's unsafe about it?   Aside from the effect on his liver and pancreas and adrenal glands and carbohydrate metabolism and skin, you might be suppressing his immune system.

Here's Stinky, the Shih T'zu.  He doesn't look too bad from a distance (although this is a day after a good bath and trim).  He (I do believe) had an allergy problem.  His previous doctor prescribed tablets with a little cortisone, plus antihistamine.  He also started in March giving him a stiff dose of Depo Medrol every two months.  Some dogs might do okay with that.  On the other hand...

Take a closer look at his legs.  Stinky (like many dogs) has always harbored a few Demodex mites (a present from his mother).  Unfortunately, when Stinky got a big enough load of Depo Medrol on board, it suppressed his immune system just a little too much and the mites took off like gangbusters.  These legs don't look good, and this is two days after his bath, trim, and starting antibiotics for the secondary skin infection, and ivermectin for the mites.

These eyelids are what really hurt him, though.  They were so painful that we had to anesthetize him to clean them up the first time.  We can treat the mites, and we can treat the secondary Staph bacterial infection.  The bad thing is this: it's only been three weeks since his last Depo Medrol injection.  That means his immune system is going to stay suppressed for a while.  We may not make much progress this first month.  Drugs help, but we need his own body defenses working in order for him to get well.

There is a place for Depo Medrol in veterinary medicine.  You need to be pretty sure what you're dealing with, though, because once it's in there, you can't take it back.

Demodectic Mange again

Some time back I wrote a post on demodectic mange.  I had a great "before" picture, but the case was lost to follow-up.  This is a different case, and this time I do have the "before" and the "after" pictures.

Shadow is a youngster who suffered a grievous injury to her left front leg.  After a period of two weeks of trying to salvage the limb, her immune system was shot, and the demodex mites had gone crazy.  Many hair follicles were damaged and secondarily infected and bleeding. This is the kind of case that lets you know where the term "red mange" came from.  Her leg had to be amputated, and treatment was begun for the demodex.   She had been treated for several weeks at this point, but the treatment regimen wasn't really intensive enough.  This picture was taken on her first visit to KVC.  She looks miserable, and she was.

We started her on a higher dose of cephalexin (antibiotics) than the previous doctor, daily dosage of ivermectin, and medicated baths twice weekly.  I also prescribed a nutritional supplement called Immuplex.  It's supposed to boost the body defense system and she surely needed that.

Shadow is much happier these days.   She will probably remain a carrier of the mites in small numbers (as most normal dogs are), and we will try to minimize stressful events in her life that might get her resistance down.  Motherhood is out of the question for her, as she would likely relapse, plus producing puppies with the same problem... plus she might lose her sweet, girlish figure.

Hamster surgery

As pocket pets go, the hamster can be a little demanding.  If not handled regularly, they can become aggressive, and they are great escape artists.  On the other hand, they can be mighty cute.

Little "Reighty" here had two skin tumors.  One looked  like an inflamed wart, and the other looked almost exactly like someone had slipped a Juinor Mint under his skin (which makes me think it may be a melanoma - pathology results will take a few days to get back).  Naturally, with a fragile little guy like this, you worry about anesthesia, but good old Sevoflurane gas worked great. Five minutes after his tumors were removed and his skin sutured, he backed his head and shoulders out of the mask (that accomodates a dog's nose).  In ten minutes he was walking around his cage.

It's really cool to see folks as committed to the health of a pet whose retail value is about one tenth the cost of his care.  Just like with dogs, cats or whatever:  I don't just want a pet, I want this pet.  Maybe someone could even learn to love me...though I have outgrown my cute stage.

Why dogs stink

"He smells like a dog", the client says.  Being as he is a dog, this doesn't seem to me to be a problem, technically.   If, being a dog, he smelled like, say, a camel -- now that would be a problem.  Of course, this is not the truly stinky dog. Every dog has a tendency to smell a little strong when wet.  If you can love your dog when he's wet, then you really love your dog.  Something about being wet, or even just a really humid day, brings out that "doggy" odor.  That's not too bad, though.  Nothing a little bath or a little deodorant (like Elimin-Odor, or Fresh-n-Clean) won't fix.  In fact, some clients complain about the dog smelling "doggy" when I personally cannot even detect an odor.  Admittedly, my nose is not sensitive at this point, so I do ask the staff to come in and give their viewpoint (smellpoint?).

Then there is the ever popular, "let's find something dead and roll in it".  It's a taste treat, a fashion accessory and a designer fragrance.  Again, nothing a bath (or two) won't cure.

Some dogs, however, are truly stinky.   A small minority of stinky dogs have an odor that arises from an internal illness.  Dogs with chronic and advanced kidney failure can have so much waste accumulating in their bloodstream that it makes their breath smell like ammonia (or urine).  Some seriously unregulated diabetics have so many ketones (fat break-down products) in their blood that their breath smells like acetone (the stuff in nail-polish remover).  These are not going to be long-term stinky dogs.  In fact, without some intensive care they are not going to be long-term alive dogs.

Long-term stinky dogs tend to either have personal hygiene problems, anal sac problems, mouth problems, skin problems, or ear problems (often extensions of skin problems, and I will discuss ear problems in more detail in a future post). 

The personal hygiene problems are worst for long-haired pets.  If you have lots of fringe around your mouth, food and saliva can lodge there and cause odor problems.  Long hair around your hiney needs to be kept trimmed.  Otherwise, the first soft stool hangs up and starts a "snowballing" effect.  It's hard to stay clean if you go to the bathroom with your pants on.  Dogs with deep skin folds also have odor problems with yeast and bacteria growing in the valleys.  This would include the English Bulldogs, the Chinese Shar-Pei, any "smashed face" bug-eyed dog, and some obese dogs.  Spaniels sometimes have folds in their lower lips that catch food and saliva.  You need to keep the folds clean. In some extreme cases, plastic surgery may be needed to eliminate the offending creases.

We have discussed basic dental care in previous posts.  The gunk in a diseased mouth stinks, and if you have an itchy dog, they will be spreading that goo on their skin wherever they chew themselves. Sweet.

Really itchy dogs (or pruritic dogs, as we scientists would say) are usually stinky if the problem is long-term.   The really itchy dog chews and scratches himself constantly.  This traumatizes his skin.  Often you can see sore places where he has actually broken the skin in an attempt to relieve his itching.  The skin attempts a protective response when continually assaulted in this fashion.  Most of us are familiar with the formation of calluses in skin areas that take a lot of wear and tear.  In dogs, the constant scratching does some other things as well.  It speeds up the process of new skin formation and maturation, though this is not particularly helpful. When you shortcut a 3-week process, the results are not as good as if you "did it right".  That's why the skin begins to flake: it's just not built as well as it should be.  Another thing that happens is that the oil glands in the skin get over-active.  This is a fatty secretion, and when produced in excessive amounts, it gets rancid pretty quickly.    This rancid odor will therefore develop with many chronically itchy dogs, no matter what the underlying cause for their problem.  Thus, dogs with yeast infections, bacterial infections, mange mites, allergies or contact sensitivity all "smell mangey".  Give them a bath and they will be stinking again in very short order. Their skin continues to crank out the grease, which goes rancid in a hurry.  The technical name for this situation is seborrhea. 

Medicated shampoos (benzoyl peroxide, colloidal sulfur, coal tars) will help abate the excessive flaking and greasiness, but you must find the underlying cause and treat that.  The stinkiness would not be happening if the itchiness were not happening.

Acceptable Stinky Dog Treatment Plan:

1. Find the source of odor:  mouth, ears, hiney, skin or combination thereof

2. Find the underlying causes and treat all of them. 

Unacceptable Stinky Dog Treatment Plan: throw dog outside.