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INTRODUCTION
Pyoderma and recurrent pyoderma have a high
incidence in small animal practice and can be
frustrating to treat.The treatment protocol should be
formulated specifically for each individual case.
Resolution of secondary pyodermas necessitates
identification of the underlying problems and
successful treatment of the primary condition. Skin
infections can be treated topically, systemically or by
combination of these. This article summarisestreatment strategies for pyoderma with special
emphasis on chronic and recurrent pyodermas.
CLINICAL SIGNS
Dogs with superficial pyoderma may present with a
range of lesions, in any combination.These include
pustules, papules, crusting, epidermal collarettes,
alopecia, scaling, erythema, prur itus and
hyperpigmentation.Which clinical signs are present
in each individual case depends on many factors
including the underlying condition as well as the
stage of infection when the animal is examined.
Certain breeds also tend to produce certain types of
lesions at a higher frequency. Different lesions have
different diagnostic power, e.g. follicular pustules,
although not found commonly, can only be caused
by a small number of diseases with pyoderma being
one of the most common (Ihrke,1987,Mason,1991)
DIAGNOSIS
The diagnosis of canine pyoderma is based on
compatible clinical signs in combination with
cytology consistent with bacterial infection
(pyogranulomatous inflammation with extra- and
intracellular cocci on cytology). With a bit of practice and experience it is easy to perform
cytology in general practice; equipment needed are
slides, a staining system (e.g. Diff Quik or RapiDiff)
and a good microscope.Trial antibacterial therapy is
occasionally useful in the diagnosis of canine
pyoderma. Swabs for bacterial culture and sensitivity
testing are only occasionally used to confirm the
diagnosis and to choose an appropriate antibiotic in
non-responsive cases. For deep pyoderma a skin
biopsy should be taken under sterile conditions and
the specimen transferred to a sterile transport
container containing a moistened gauze swab.Another possibility to prevent surface contamination
is to remove the epidermis prior to taking the biopsy.
TREATMENT
Treatment of canine pyoderma depends on the
extent and depth of the lesions, owner and patient
compliance and the underlying disease. Topical
and/or systemic drugs can be used.
Topical treatment
Topical antibacterial therapy is useful as a sole
therapy or as an adjunct to systemic antibacterials.
Topical medication is available as shampoo, rinse,spray, gel and cream.
Shampoos
Medicated shampoos are commonly used. In
addition to the mechanical action of removing tissue
debris, removing the exudates and reducing the
bacterial population on the skin can aid in the
resolution of bacterial infections of the skin and help
reduce the frequency of relapses in recurrent
pyoderma. In acute cases of superficial and deep
pyoderma shampoos play a supporting role to
achieve faster resolution of clinical signs during
systemic therapy.
Shampoo therapy not only has a cleansing effect,but
also rehydrates the skin and makes the dog feel more
comfortable.Medicated shampoos should be chosen
for each dog and each case individually based on the
coat condition (e.g. dry or oily seborrhoea). In severe
cases it might be necessary to wash the dog every
second day or even daily until remission is achieved.
This can usually be reduced to weekly or fortnightly
as soon as the pyoderma is in remission. Owner
compliance is important as this form of therapy is
very time consuming. It is important to instruct theowner carefully on how to bathe a dog as
shampooing will only be successful if the owner
allows an appropriate contact time followed by
thorough rinsing with warm water to remove
shampoo residues. Many veterinary shampoo
manufacturers produce leaflets that can provide
helpful information for owners. In long haired dogs
it might be useful to clip the dog to ensure good
penetration of the active ingredients to the skin
surface.
Antibacterial shampoos contain ingredients likebenzoyl peroxide, chlorhexidine, ethyl lactate,
povidone-iodine, hexetidine or piroctone olamine.
SMALL ANIMAL G DERMATOLOGY###UK Vet - Vol 12 No 1 January 2007 1
Christa Horvath DrVetMed MRCVS
SCHERING PLOUGH SENIOR CLINICAL SCHOLAR
HOSPITAL FOR SMALL ANIMALS, EASTER BUSH VETERINARY CENTRE, ROSLIN MIDLOTHIAN. EH25 9RG
Ariane Neuber DrVetMed CertVD Dipl ECVD MRCVS
CHILTERN REFERRAL SERVICES, CHALFONT ST GILES, BUCKS. HP8 4AB
GREAT WESTERN REFERRALS, SWINDON, WILTS. SN1 2NR
Management of canine pyoderma
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Shampoos licensed for use in dogs in the UK are
listed in Table 1. Benzoyl peroxide, organic iodine
compounds, chlorhexidine and triclosan are able to
kill Staphylococcus intermedius on the skin (Kwochka
and Kowalski, 1991). Each of the active components
listed above has different properties:
G Benzoyl peroxide lowers the pH of the skin and
disrupts the microbial cell membranes. (Burkhart
et al ., 2000).Additionally it is follicular flushing,
keratolytic and strongly degreasing. It is very
useful in deep pyoderma. Benzoyl peroxide is
also drying and bleaching and should therefore
not be used in dry seborrhoea and owners
should be warned about the bleaching effect.
G Chlorhexidine is less irritating than benzoyl
peroxide and is therefore preferable in dogs with
sensitive and dry skin. It is effective against many
Gram positive and Gram negative bacteria with
the exception of some Pseudomonas and Serratia
strains. Chlorhexidine also shows a good residual
antibiotic effect.
G Ethyl lactate is hydrolysed to ethanol and lactic
acid, which lowers the skin pH. Its mode of action is therefore similar to benzoyl peroxide
(de Jaham,2003).
Creams and ointments
The use of various antibiotic creams or ointments is
limited to smaller infected areas. In conditions like
intertrigo, canine acne, callus pyoderma or pedal
folliculitis and furunculosis they can be very helpful.
For larger areas creams cannot be recommended due
to the amount that has to be used. Creams and gels
may contain agents like mupirocin, fucidic acid and
bacitracin, all of which have a narrow antibacterial
spectrum (Table 2).The antibiotic should be able to
permeate superficial skin and not be inactivated by
tissues, fluids or proteins. Clinically, the frequency of
staphylococcal resistance to fucidic acid and
mupirocin is low.Fusidic acid (produced by Fusideum
coccineum) and mupirocin (produced by Pseudomonas
fluorescens) inhibit protein synthesis. Mupirocin has
good activity against Gram-positive cocci, is
bacteriostatic, rather than bactericidal and is not
systemically absorbed. Its penetration is very good,
even in deep pyoderma and therefore it can be used
for interdigital abscesses, chin pyoderma or pressure
point pyoderma. Bacitracin consists of one or more
antimicrobial polypeptides produced by certainstrains of Bacillus licheniformis. It is active against
Gram-positive bacteria and some Gram-negative
cocci. Resistance to bacitracin in staphylococci has
been described (Kruse et al .,1996) and Gram-negative
bacteria are intrinsically resistant to bacitracin,
presumably as a consequence of their outer
membrane permeability barrier. However, acquired
resistance is rare (Werner and Russell, 1999).
Systemic therapy
The vast majority of bacterial skin infections in dogs
are caused by Staphylococcus (S.) intermedius, althoughProteus, Pseudomonas and E. coli can be isolated,
especially from deep infections. For systemic
antibacterial agents prescribe an appropriate
antibiotic (based on sensitivity testing) that
penetrates skin, for an adequate period of time and
avoid concurrent use of corticosteroids.
G For superficial pyoderma prescribe the antibiotic
for a minimum of 21 consecutive days or for
7-14 days after clinical cure.
G Deep pyoderma should be treated for a minimum
of 4 to 6 weeks with treatment continuing for 2
weeks after complete clinical cure.
SMALL ANIMAL G DERMATOLOGY### UK Vet - Vol 12 No 1 January 20072
Brand name Agent
Coatex, VetPlus Chloroxylenol
Salicylic acid
Sodium thiosulfate
Etiderm, Virbac Ethyl lactate
Benzalkonium chloride
MalAcetic, DermaPet Acetic acid
Boric acid
Malaseb, VetXX Chlorhexidine
Miconazole
Paxcutol, Virbac Benzoyl peroxide
Sebomild P, Virbac Ammonium lactate
Piroctone olamine
Essential fatty acids
Chitosanide
TABLE 1: Antibacterial shampoos
Brand name Ingredient Licensed in UK for Manufacturer
use in dogs
Fuciderm Sodium fusidate Yes VetXX
Fucidin Sodium fusidate No VetXX
Flamazine cream Silver sulphadiazine No Smith & Nephew
Betadine Povidone-iodine No Seton Healthcare Group
Bactroban Mupirocin 2% No Polyfarma Ltd, Smith Klein Beacham
Surolan Miconazol, polymyxin Yes Janssen Animal HealthB, prednisolone
TABLE 2: Antibacterial ointments
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If treatment is stopped just as the lesions clear, there
is usually relapse. It is important to explain this to the
owner from the beginning of the treatment and
stress the importance of keeping appointments for
checks.All cases should be re-evaluated within three
weeks and again before discontinuation of antibiotics
by a vet.Sometimes it is necessary to clip parts of the
hair coat to better visualize the skin for lesions.
Some antibiotics (penicillin,amoxicillin, streptomycin,
and ampicillin) are unsuitable for treating pyoderma
because they do not achieve therapeutic
concentrations in the skin. Ideally, the antibacterial
should have a narrow spectrum. In most cases it ischosen empirically after inflammatory cells and
cocci have been demonstrated on skin cytology.The
choice can be made on the basis of culture and
sensitivity testing, but this is only strictly necessary in
cases that appear resistant to therapy or when rodshaped bacteria are found on cytology. Drugs
commonly used include narrow spectrum agents
(e.g. clindamycin and lincomycin) and broad
spectrum agents such as cephalosporins (first
generation), (Frank and Kunkle, 1993) potentiated
sulphonamides and clavulanic acid-potentiated
amoxicillin (Table 3). Most veterinary dermatologists
reserve fluoroquinolones for use after culture and
sensitivity testing or for staphylococci which prove
resistant to the drugs above (Ihrke, 1987, Paradis et
al ., 1990, Paradis et al ., 2001,Ganiere et al ., 2004).
Failure to respond
If there is no response to treatment, the chosen
SMALL ANIMAL G DERMATOLOGY###UK Vet - Vol 12 No 1 January 2007 3
Fig. 1b: Alopecia, hyperpigmentation, scaling and erythema,
closer view.
Fig. 1a: Superficial spreading pyoderma.
Fig. 1c: The same dog after treatment with cephalexin;
the underlying cause was atopic dermatitis.
Fig. 2b: Superficial pyoderma beneath the axillae.
Fig. 2a: Superficial pyoderma on the ventral abdomen.
Fig. 2c: The same dog after treatment with cephalexin;
the underlying cause was food hypersensitivity.
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SMALL ANIMAL G DERMATOLOGY### UK Vet - Vol 12 No 1 January 20074
Drug Product Manufacturer Drug class Licensed in Recommended
Spectrum UK for dogs dose/kg for
pyoderma
Erythromycin Erythromycin Abbot macrolide no 15 mg q 8h
tablets Laboratories Ltd antibiotic; gram
Sovereign positive and
gram negative
Lincomycin Lincocin tablets Pfizer Animal lincosamide yes 20-30 mg q 12h
Health antibiotic; gram
positive and many
anaerobes
Cephalexin Ceporex Schering-Plough 1st generation yes 20-30 mg q 8-12h
Animal Health cephalosporin;
Rilexin Virbac Animal gram positive and
Health UK gram negative
Cefadroxil Cefa-Tabs Fort Dodge 1st generation yes 10-22 mg q 12h
Animal Health cephalosporin;
gram positive and
gram negative
Ciprofloxacin Ciproxin tablets Bayer Animal fluoroquinolone; no 5-15 mg q 12hHealth gram positive and
gram negative,
Mycoplasma
Enrofloxacin Baytril Bayer Animal fluoroquinolone; yes 5-10 mg q 24h
Health gram positive and
gram negative,
Mycoplasma
Marbofloxacin Marbocyl Vetoquinol UK fluoroquinolone;
Ltd gram positive and yes 2-5 mg q 24h
gram negative,
Mycoplasma
Clavulanic acid- Synulox Pfizer Animal gram positive and yes 12-25 mg q 8-12hpotentiated Health gram negative
amoxicillin
Trimethoprim- Norodine Norbrook gram positive and yes 15-30 mg q 12h
sulphonamide Laboratories gram negative
Tribrissen Schering-Plough
Animal Health
Clindamycin Antirobe Pfizer Animal lincosamide yes 5-10 mg q 12h
Health antibiotic; gram
positive and many
anaerobes
Doxycycline Ronaxan Merial tetracycline yes 2.5-5 mg q 24h
TABLE 3: Systemic antibiotics
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UK Vet - Vol 11 No 1 January 2006 5
antibiotic may have been inappropriate for the
suspected infection. At this point culture and
sensitivity testing should be performed.
Relapse
In cases that respond to antibiotics but relapse within
a week after treatment has been discontinued,
consider prescribing a longer course of treatment.
Potential underlying causes should be investigated e.g.
with uncontrolled atopic dermatitis regular relapses
of the secondary pyoderma is to be expected.
Immunomodulatory therapy
Immunomodulation has been attempted with
various agents, including levamisole and cimetidine
(an H2 histamine receptor blocker) but specific
SMALL ANIMAL G DERMATOLOGY###
Fig. 3a: Collie with severe FAD.
Fig. 3b: Chronic superficial pyoderma with alopecia,
erythema, hyperpigmentation and crusts.
Fig. 3c: Skin lesion in remission after a course of
cephalexin and flea treatment, nice hair regrowth.
Fig. 4b: Multiple draining tract, closer view.
Fig. 4a: Generalised deep pyoderma in a 1-year-old
Mastino Neapolitano with generalised demodicosis.
Fig. 4c: The same dog three months after treatment with
clavulanic acid potentiated amoxicillin and ivermectin.
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UK Vet - Vol 12 No 1 January 20076
details on efficacy have not been published.The use
of these drugs is reported but the author has no
experience with the dose rates. (Scott et al . 2001).
Levamisol restores normal numbers of lymphocytes
(T cells) thus leading to normal function of these
cells. Cimetidine may act by reversing T-suppressor-
mediated immune suppression (Kwochka, 1993).
However proof of immuno-incompetence in
veterinary medicine is not routinely available which
implies that the use of levamisol for this purpose is
anecdotal.
Various bacterins (autogenous vaccines e.g. produced
by the Royal Veterinary College), S. aureus phage
lysate (Staphage Lysate, SPL, Delmont Laboratories,
Swarthmore, US.) and Propionibacterium acnes
(Immunoregulin, Immunovet) have been used, with
the autogenous preparation being the only product
available for use in the UK.The mechanism of action
is unknown but they are hypothesised to improve
cell-mediated immunity, impacting on non-specific
and humoral immunity (Nesbitt and Schmitz, 1977,
DeBoer,1990,Scott et al . 2001).Protocols for the useof bacterins vary from 0.5 ml subcutaneously twice
a week to 1-2 ml weekly, duration of treatment
should be at least 10 weeks with success rates ranging
from 30-70% (DeBoer, 1990, Kwochka, 1993).
DeBoer reported a long-term success rate of 50%
with Staphage Lysate over a period of 22 months
(DeBoer et al ., 1990).
In a recently published study the clinical efficacy of
staphylococcal autogenous bacterin was evaluated in
dogs with idiopathic recurrent pyoderma. In all dogs
S. intermedius was cultured. Both groups received a4-week course of antibiotics. One group received
additional injections of the bacterin, the other
received no additional treatment. Comparison of
lesion scores of the control group and treated group
showed significantly higher scores in the control
group compared to the group receiving bacterin.No
adverse reactions to bacterin therapy were noticed
(Curtis et al ., 2006).The dogs in this study were still
treated at the end of a 9-18 month follow-up period.
These results are quite promising, but further studies
should be performed with large numbers of dogs
and a long follow-up period. Currently there are no
other licensed products available in the UK.
RECURRENT PYODERMA
Long term management of recurrent superficial or
deep pyoderma relies on various factors including
the identification of underlying causes and owner
compliance. Recurrent pyoderma is commonly a
lifelong disease and therefore regular re-examination
and detailed discussion with the owner about the
underlying disease and the forms of therapy that are
available are very useful. If owner compliance and
patient temperament allow lifelong shampoo
therapy, this can be a very effective form of therapywith very low occurrence of side effects and less
worries about the potential to induce antibacterial
resistance.The frequency of washes has to be assessed
in each case individually by the owner and the
veterinary surgeon. Localised lesions can be treated
with antibacterial creams. Immunomodulatory
therapy can be added as mentioned above. If an
underlying cause can be identified and successfully
treated, the pyoderma might resolve, otherwise
extended antibiotic regimes can be used. Recurrent
pyoderma can be a difficult disease to manage.
Success is closely linked to owner compliance.
Owners must be willing to invest a lot of time and
money in the management of their pet.
For long term management various treatment
protocols are suggested. After clinical remission on
full dose antibacterial therapy consider:
1. Maintenance antibiotic therapy using suboptimal
doses to maintain remission. The chosen drug
should have minimal side effects and little
potential to develop resistances. For example, if
the dog requires 500 mg of cephalexin twice a
day, this dose should slowly be tapered to 250 mg
once a day or every other day.2. Pulse therapy at full dose on some days, with
drug-free days in between has been used
(Kwochka, 1993).The number of days on and off
medication varies from patient to patient and
must be individually assessed.
For pulse therapy the full therapeutic dose should be
given. For example a dog is prescribed 500 mg
cephalexin q 12h in Week 1, in Week 2 the dog
receives no antibiotics, in Week 3 cephalexin is given
as for Week 1 (one week on, one week off). If this
regime works, the time off periods can be extendedgradually (DeBoer, 1990).
CONCLUSION
Single episodes of pyoderma should be treated as
necessary with topical and/or systemic antibacterial
treatment at the right dose and for an adequate
period of time. Recurrent cases of pyoderma require
a more extensive work-up with identification of the
underlying condition, and if possible, correction
thereof.An individual management programme that
might change over time depending on the
requirements of the individual patient, should be
formulated.This might include the use of shampoos,immunmodulatory treatment and/or pulse therapy
with antibiotics. In all cases efforts should be made
to identify an underlying cause.
REFERENCE
BURKHART, C. N., SPECHT, K. and NECKERS, D. 2000 Synergistic
activity of benzoyl peroxide and erythromycin. Skin Pharmacol Appl Skin
Physiol 13 292-6.
CURTIS, C. F., LAMPORT, A. I. and LLOYD, D. H. 2006 Masked,
controlled study to investigate the efficacy of a Staphylococcus
intermedius autogenous bacterin for the control of canine idiopathic
recurrent superficial pyoderma. Vet Dermatol 17 163-8.DE JAHAM, C. 2003 Effects of an ethyl lactate shampoo in conjunction
with a systemic antibiotic in the treatment of canine superficial bacterial
SMALL ANIMAL G DERMATOLOGY###