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However, Ask Dr Mike is available only to subscribers of our Vetinfo Digest.Pyoderma (bacterial skin infection), Interdigital Pyoderma in DogsPlease do not send questions if you are not a subscriber. to keep the large amount of information on www.vetinfo.com free to our readers.
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Interdigital pyoderma and pododermatitis
Vulvar fold pyoderma/cellulitis
Lip Fold Pyoderma
Skin infections (pyoderma)
Recurrent skin infection in Lab
Skin condition in French Bulldog
Bacterial skin infection
Interdigital Pyoderma
also see Itching
also see Hot Spots or Moist Pyoderma
also see Allergy
also see Interdigital Cysts
also see Skin Problems
Interdigital pyoderma and pododermatitisQuestion: Dear Dr. Richards:
I have an 11-year-old shelty named Ben, whom the family love
very much.
He has a lesion on his right forepaw that seems to fit the
description of "interdigital pyoderma" that you mentioned in a web-posted article
involving a dog named Angie. I would deeply appreciate your advice on
alternatives to surgery. His history may be summarized as follows.About 2.5 years ago, I noticed that Ben had what appeared to be a small
puncture between the outer two toes of his right forepaw at the
juncture of the two toes and more towards the top of his paw than the bottom.
The wound appeared neat as if made by the tip of an icepick. Ben walks
regularly in a canyon that has plenty of foxtails that might have
produced such an outwardly appearing puncture. After several weeks,
the wound appeared to heal. But, with any daily walking of more than about
a mile or so, it would re-open enough to bleed. He also walks with his
right paw pidgeon-toed inward and with a slight limp that is more
pronounced when walking down hill.After several months, I took him to three different vets over the next
year, none of whom knew what to make of the lesion, but all agreed that
a foreign body should have worked itself out by that time. A fourth
vet said that Ben had a tumor between his toes that had to be removed, so I
okayed the surgery in February of 2001. This vet #4 said that the
tumor was about a centimeter in diameter, but I personally was never able to
feel it. Vet #4 removed as much tissue as possible without risking
damage to the paw and toes. About two months later, the lesion
returned between the adjacent pair of toes, and has subsequently spread very
slowly up the paw (as may be seen in the attached images of 4/1/01 and
10/21/01).The biopsy of the surgically removed tissue concluded the following.
No evidence of malignant change in the tissue, but rather inflammatory and
not neoplastic. Such a tissue reaction can be due to foreign body
penetration or deep-seated chronic bacterial infection. Fragments of
keratin appeared to be acting as foreign bodies, suggesting that
rupture of a follicle may have released material which incited a focus of
foreign body reaction. Neutrophila were seen mingled with
macrophage-type cells, with neovascularity and granulation tissue
formation seen in surrounding tissue. In short, the diagnosis was
"focal pyogranulomatous inflammation, with secondary granulation tissue
and tract formation."I next took Ben to a 5th vet this past July who diagnosed the lesion as
"interdigital granuloma" and had me give Ben a 30-day prescription of
Baytril, along with regular Epsom Salts soaking of the paw. The lesion
got a little bit better, but never went away, and is now much worse as
shown in the attached image of 10/21/01. Ben also has periodic dark
skin bumps that itch a great deal and eventually fall off, only to be
replaced by 3-4 more elsewhere on his body. He has also been getting
occasional yeast infections in his left ear. But outside of these skin
problems, his health is excellent according to all vets who have
examined him. By the way, he gets two small daily feedings of Science
Diet, a mix of half the "sensitive skin" formula and half the "lamb
meal and rice" formula.So what should I try next? You suggested NeoPredef (Rx) and some sort
of systemic medication as a possible treatment for Angie. I want to
avoid a second surgery for Ben, as it would have to take much of his
right forepaw. Is there any way I can stop the growth and discomfort
of Ben's lesion? I would be so very grateful if you could suggest some
actions I might take. I cannot resist also showing you what a
beautiful dog he is (third attached image).Very sincerely, Charles
Answer: Charles-
There are several possible approaches to the sort of problem that you
are having with Ben that might help. I do not practice in an area in which
foxtails are found, so I have very little opportunity to see the wounds
from these. We have seen around three dogs with foxtail problems after
trips out West. These do seem to be capable of causing long term
infections that don't stop until they are removed. However, since surgery has been
done once this seems like less of a possibility. I'm just not sure that
the continued presence of a foreign body can be ruled out and if there is
one, surgery still might be the best option.We do see a lot of dogs with pododermatitis and interdigital pyoderma
who have persistent cystic sores between the toes that often open and drain,
though. Over the years these have been extremely frustrating to treat
successfully with any one approach. So the following is a list of
things that have worked in at least a few dogs, with some notes about how we
use them:Mupirocin ointment (Bactoderm Rx). Actually, we just started using this
ointment more frequently. We like it so far and it seems to be helping
one of our chronic cases some -- but it is sort of early to be sure.Metronidazole (Flagyl Rx) has worked wonders for two or three cases of
interdigital cysts in our practice. We had one dog who had been to four
or five vets prior to moving into our area and had been treated with
everything else on our list. He responded within ten days to
metronidazole and the cysts actually cleared up. They have returned a couple of times
now but have continued to respond to metronidazole. Right now, this is our
favorite treatment for resistant cases of this problem but we could just
be on a lucky streak since other things have seemed to work well for a
while in the past.Doxycyline, like metronidazole, has worked well for a couple of dogs who
did not respond to treatment with other antibiotics. These cases have
been a little more sporadic for us but it still seems worth a try to us.Fluoroquinolones (Baytril Rx, Dicural Rx, Orbax Rx, others) are the most
commonly recommended antibiotics in the dermatology literature. These
are broad spectrum antibiotics that generally penetrate tissue well. Even
though your vet chose the antibiotic group to treat with that is usually
considered best, sometimes fluoroquinolones just don't work.Clindamycin (Antirobe Rx) is an antibiotic that has good activity
against anerobic bacteria which seem to be involved in some cases of
interdigital cysts. It is often used in combination with fluoroquinolones but can
also be effective alone in some dogs.Cephalexin ( Keflex Rx) is our general favorite antibiotic for skin
disease, especially in older dogs. We are comfortable using it long
term, which is often necessary to control skin infections. It seems to be
among the safer of antibiotics, although no antibiotic is totally risk free.
If there seems to be any response to cephalexin early in treatment we
usually try it for at least three weeks. I like trimethoprim/sulfa combinations
(Tribrissen Rx, Bactrim Rx, others) but am reluctant to use these in
older dogs because the side effect we see most often is reduction in tear
production and older dogs often have problems with tear production as it
is.A bacterial culture and antibiotic sensitivity testing might be helpful
in choosing an antibiotic but our experience with this has not been overly
encouraging. We get a lot of staph bacterial growth, usually sensitive
to most antibiotics we use even in infections that haven't responded to a
couple of the antibiotics -- so we figure that we aren't really growing
the organism causing the problem most of the time.So our basic approach is to start with cephalexin and then move on to
the other medications on the list, except that we often use cephalexin and
metronidazole together rather than withdrawing the cephalexin. We have
been using the topical mupirocin as an additional therapy in the last few
cases but don't have much feedback on it, yet. We use fluoroquinolones last,
mostly based on expense but also because we like to have an antibiotic
that we don't use much, too. That is just a practice quirk, though. It would
be easy to argue that using them first might save money if they work best.I hope that this helps you help Ben.
Mike Richards, DVM
11/11/2001
Vulvar fold pyoderma/cellulitis
Question: Katie is being seen by a dermatologist for
an ongoing skin problem, Vulvar fold pyoderma/cellulitis. She has been on a high
dosage of antibiotics for several months. We have seen some improvement in her
skin condition.
Answer: Vulvar fold pyoderma can sometimes be controlled through surgery to reduce the folds. This should be done by a surgeon who is familiar with the procedure, though.
Mike Richards, DVM
9/22/2001
Question: Dr. Richards:
I have a 10 year old golden retriever. From time to time over the past 5
years or so, she's developed a bad, rotten fish type of smell on the outside
of her mouth, under one of her bottom lips, in the fur area. Her fur in
that area becomes a little sticky and a little red and seems to bother her a
little. I usually clean it up with the chlorhexaderm oral solution and put
some anti-biotic ointment on it and it usually clears up within a few days.Any ideas what this could be from? Her teeth are in good shape and she gets
them brushed every other day or so, so I don't think it's from dental
disease.Thanks. Vanessa
Answer: Vanessa-
It sounds like you are describing a problem that is referred to as "lip
fold pyoderma". This is infection in folds of the lip that usually occurs
on the lower lips, often right at the point that the upper canine tooth
touches the skin of the lower lip when the mouth is closed.There is no problem with using chlorhexidine gel or benzoyl peroxide
shampoo to control these infections, if topical treatment will work.
Sometimes oral antibiotics are necessary to get control of these
infections. If you find that this problem gets worse over time, or if you
get tired of treating it intermittently, reconstructive surgery of the
lower lip (cheiloplasty) will usually resolve the problem and may even be
less expensive than repeatedly using medications, over time. This is not a
technically difficult surgery and most general veterinary practices can do
this. This problem is rarely related to the teeth, other than occurring
where the upper canines touch the lips in many cases.Hope this helps some.
Mike Richards, DVM
1/3/2001
Question: Dear Dr. Richards:
My dog, Sammy, is a 75-lb mixed breed. He looks like a Shep/Rotty mix.
Three months ago he would yelp when I would touch a spot on his back; near
and around his withers. When I took him to the vet, we couldn't do anything
to reproduce this symptom. Accordingly, the vet prescribed Prednisone because
he thought Sammy had a pinched nerve. My dog did not do well on Prednisone
and I weaned him off it in about a week. About six days later I brought him
back to the vet because his skin was flaking (dandruff) and he was diagnosed
with a staph infection and given Ceflexin (sp?) which worked well. We didn't
make any connection back then.Now, three months later, the same sequence of events has occurred. First
the yelping -- the vet thought it might be bone-related -- and then the itch
and scaling. We finally realized the pain he had three months ago was
probably associated with the staph infection, just like it is now.What can be causing this infection, how can I treat it, and more
importantly, is there any way to avoid it occurring in the future? Is it
contagious to humans or other animals? He enjoys the local dog-park and I'd
hate to have to avoid going there with him in the future.Thanks, Brad
Answer: Brad-
Skin infections (pyoderma) occur as primary infections (no underlying
cause) and as secondary infections to other diseases, especially allergies,
parasites and immune system disorders. It can be very hard to figure out
whether a skin infection is primary or secondary in some dogs. The presence
of pain or tenderness in the areas that becomes infected, prior to visible
signs of infection, makes the probability of this being a secondary
infection a little higher, probably. On the other hand, when the clinical
signs clear up with antibiotic therapy alone, it makes a primary bacterial
skin infection more likely --- so essentially you have a toss-up going on
and you and your vet will have to work through this over time to determine
what is going on.The biggest mistake that people make when treating skin infections is not
treating them long enough. If an infection responds to antibiotics and then
recurs, it is a really good idea to use antibiotics for at least 6 weeks
and possibly 8 or more weeks, to try to eliminate the infection. If that
doesn't work, it may be necessary to treat intermittently, or even to treat
continuously, to control some skin infections. Cephalexin is usually a
good choice since most of the time these are staph skin infections.It is a good idea to make sure there are no fleas, no mites (Demodex or
Sarcoptes) and to pay attention to when the skin infections occur to try to
see if there is a link to something, or if they occur the same time each
year. This gives a hint about underlying causes.I know of no evidence that staph skin infections from dogs are contagious
to humans and there are only scattered reports in which vets worried over
potential contagiousness between dogs. Most of the time these are normal
bacterial residents of the dog's skin that just get out of hand because a
particular dog has some problem controlling them.Good luck with this.
Mike Richards, DVM
11/19/2000
Recurrent skin infection possible
Question: Dear Dr. Richard:
I have just become a subscriber to your service and look forward to having
you answer future questions.My 2 year old black lab has been diagnosed with a bacterial skin infection.
He does not have any rash and is not scratching. He has been on antibiotics
for 2 weeks and still is loosing a lot of hair. My vet does not seem
concerned about the hair loss. This is his third time with a skin infection.
They ruled out autoimmune problems the 2nd time he had this problem. Each
time the symptoms are a little different. What do you think?Lisa
Answer: Lisa-
Labrador retrievers shed a lot, at least based on the ones in our practice.
If there is a lot of shedding but there are no visible thin patches in the
hair coat it is possible that this is just normal shedding behavior.On the other hand, if there is thinning of the hair coat, scales in the
hair coat, small patches of hair loss with scaling along the edges, red
bumps in the skin, small scabs or visible pustules (pimples) on the skin
then a bacterial skin infection is likely. Labradors are also somewhat
prone to having bacterial skin infections and if the signs above are
present and there is not much itchiness that would be pretty typical of
bacterial skin infection (pyoderma). It can take a fairly long course of
antibiotics to control pyoderma in dogs, sometimes several months or more.There can be underlying causes for recurrent skin infections, such as skin
parasites (especially fleas), allergies, immunodeficiency disorders (these
are actually hard to completely rule out), hypothyroidism and
hyperadrenocorticism. The hormonal disorders are pretty uncommon in young
dogs, though.I hope that this helps some. I would be glad to try to help more if you can
send more information on the clinical signs that you have seen, when they
started and what has been done to treat these problems.Mike Richards, DVM
10/17/2000Skin Condition in French Bulldog
Question: Cowboy, my Frenchie, has developed some small patches on his forehead
that look and feel like small bumps.
They don't seem to bother him. The hair is sparse or absent on these
spots; not particularly inflamed.We live in a dry, mountainous area. Therefore, I have attributed the
condition to allergies, dryness, or perhaps the need for more oil in his
diet. (He seems to crave the skin lotion I apply after a shower.) His
coat is shiny and appears healthy, maybe with some signs of skin dryness
and flakiness.We have an appointment with a new vet tomorrow to investigate this skin
situation, so, I would like a bit of input from you about this. You
have been very helpful in the past; it seems like most times you and I
are "on the same page" diagnostically. (I'm sure not a vet but a
long-time dog owner, breeder, and rescue program participant. Just have
some experience with animal health.)Look forward to hearing from you.
And again, many, many thanks...you do a great service!!
Jean
Answer: Jean-
Skin bumps on short haired breeds tend to be a sign of pyoderma (skin
infection). It is really hard to figure out what to do when these are
confined to a small area of the skin. It often seems like overkill to use
oral antibiotics for several weeks but topical treatment with antibacterial
shampoos is not too reliable. We have seen a couple of cases of demodectic
mange that presented as scattered bumps associated with hair follicles. All
of these were in young dogs, as far as I can remember. Ringworm sometimes
looks like this. A few dogs are probably having reactions to insect bites
or contact irritants. Finally, there are a number of skin tumors that occur
and sometimes they do start out looking like minor infections or benign
bumps. The odds favor a skin infection by a pretty wide margin, though.It is pretty important to check the skin out very carefully for bumps in
other places and to look for enlarged lymph nodes. Once in a while we find
a patient with a subtle generalized pyoderma that only become really
evident when it causes a few bumps somewhere.Of course, you are already taking the best step by getting your vet to
examine Cowboy tomorrow!Mike Richards, DVM
6/23/2000
Q: My friend has an 8 year old female Samoyed with a skin problem The vet is treating it with antiobiotics and the dog has been on them for 4 weeks. Started at tail with skin becoming scaly in spots. After shaving affected area skin appears to have brown rings on it. Areas clear up and hair grows back but then new areas appear on other parts of the body. We thought with the antibiotics the condition would not spread. But it is. Do you have any idea for alternate treatment? Diane
A: Diane- I would still be suspicious of a bacterial skin infection with the signs you describe, so continuing the antibiotics seems like a good idea to me. It might be worth attempting to get a culture from a skin lesion to identify the bacteria involved and get an idea of what antibiotics kill it, if this is possible. Sometimes this doesn't work and often it is expedient just to change antibiotics, making sure to stick to ones that have a good track record of helping with skin disease. Sometimes the bacterial infection has an underlying cause, such as allergies, immune mediated disease, systemic illness or skin parasites. Checking for these conditions may be necessary if the problem continues. There are veterinary dermatologists and it can be worth the drive to one for difficult skin problems. They see the resistant and atypical cases of skin disease and often can pick up patterns of disease not apparent to a general practitioner or do specialized testing not available at many veterinary offices.
Good luck with this.
Mike Richards, DVM
Q: I have a westie who develops recurrent cysts between his front paws. Our local vet pokes him full of steroids and antibiotics but they only recur so that he is seldom free from them. They are quite sore and do affect him. He is 11 years old and quite game for daily long walks, is not overweight but is stocky. Our local vet is happy with him and feels that he ought to live with the problem and just seek aid when it flares up badly. 25 years ago we had the same problem with a Jack Russell who became reluctant to exercise and became somewhat overweight ultimately causing his death. I hope that in 25 years some progress may have occurred. I do appreciate your availability on the net. I do the same as a dentist and feel; that I am being useful as I am sure do you. I hope you can help.
A: Westies are extraordinarily difficult patients when it comes to skin disease. I can understand why your vet is content with intermittent success in repressing the clinical signs. Sometimes it is hard to achieve that level of success in dealing with problems like interdigital pyoderma in Westies. On the other hand, he is likely to live a long time and I can understand your desire for a long term solution to the problem. My best advice would be to seek the help of a veterinary dermatologist if one is available in your area. Most of the time, the problem with Westies is allergic in nature. They are very prone to atopy and more prone than most breeds to food allergies. Allergy testing and hyposensitization will help many dogs with atopy. Food trials and hypoallergenic diets help with the food allergies. Intradermal skin testing still seems to be the best method of determining what a dog is allergic to for inhalant allergies (atopy) and dermatologists are the most experienced at this sort of testing in most areas. If you do not have a veterinary dermatologist available or do not think that you would be willing to do hyposensitization (usually you have to give the allergen injections yourself due to the schedule), then you may have to accept the current status. Your vet probably is doing pretty well even though it is frustrating. It does seem like we should have a better solution after all these years. I wish it were so!
Mike Richards, DVM
Last edited 11/17/04