February 2015
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Contents
What’s in
shampoos?
Active ingredients
in shampoos
Indications and
claims
Evidence on
shampoos
Pruritus
Malassezia
Bacterial
overgrowth
Dermatology
guidelines
Using shampoos in
practice
Shampoos are often used as adjunctive therapy, and sometimes monotherapy, in
the management of canine skin diseases including pyoderma, Malassezia infection,
dermatophytosis, atopic dermatitis, sebaceous adenitis, and keratinisation disorders.
There is a large and confusing range of canine shampoos on the market. Here we review
the features of the shampoos available in the UK and look at the published clinical trial
evidence on shampoos in the treatment of canine skin diseases.
What’s available?
Conclusion
February 2015
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What’s in shampoos?
The cleansing action of shampoos comes from surfactants,
oils, silicones, chitosanide), other additives (e.g. moisturisers,
which help remove dirt and grease.1 Soap, the original the
stabilisers, fragrance and colour) and active ingredients for
surfactant in shampoos, tends to irritate the skin due to its
the management of specific problems such as Malassezia or
alkalinity, and has been replaced in modern shampoos by
bacterial overgrowth, scaling and flea infestation (e.g. micon-
synthetic surfactants.1 Shampoos will often contain a mix-
azole, chlorhexidine, salicylic acid, permethrin).
ture of different surfactants together with conditioners (e.g.
Active ingredients in shampoos
Antibacterial: acetic acid; boric acid; chlorhexidine; ethyl
Reduction of scale: zinc gluconate; ammonium lactate;
lactate; piroctone.
salicylic acid; chitosanide; selenium sulphide.
Antifungal: acetic acid; boric acid; chlorhexidine;
Insecticide. Several insecticidal shampoos are available on
ketoconazole; miconazole.
general sale (legal category AVM-GSL). They contain permethrin alone, or pyrethrins + piperonyl butoxide. As they have
Emollient: aloe; colloidal oatmeal; chitosanide; essential
no residual effect they have a limited role in the management
fatty acids; glycerine; urea.
of flea infestations.
1. Trueb RM. Shampoos:
ingredients, efficacy and
adverse effects. JDDG 2007;
5: 356–65.
February 2015
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Indications and claims
A few shampoos are licensed as medicines and have specific
Most shampoos are not licensed as medicines but labels
licensed indications (see ‘What’s available’ below). These are
commonly include a description to indicate how they may
prescription-only (POM-V) products containing chlorhex-
be used. For example, “for dry scaly skin”, “for itchy dogs”.
idine alone or together with miconazole, for the treatment
Other are variously described on the labels as “soothing”,
of bacterial or fungal infections; a shampoo containing sele-
“microbial balancing, “hypoallergenic”, “soap free”,
nium sulphide for the treatment of seborrhoeic dermatitis
“exfoliating”.
(AVM-GSL); and the insecticidal shampoos mentioned above
(AVM-GSL).
Some shampoos contain ‘spherulites’ a brand name for a patented form of vesicles (or liposomes). Such vesicles can be used
as transporters for active ingredients.2 Shampoos containing ‘spherulites’ claim to have a residual effect on skin.
2. Zhang P et al.
Characterization of
spherulites as a lipidic carrier
for low and high molecular
weight agents. Pharm Res.
2013; 30: 1525-35.
February 2015
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Evidence on shampoos
There are few published clinical trials assessing the effects of shampooing in the treatment of canine skin diseases.
Pruritus
In a double-blind, placebo-controlled trial, 22 dogs with a
none with water alone). Pruritus scores were unchanged by
history of allergic or idiopathic pruritus for at least 4 weeks
the end of the trial showing that the effect of shampooing is
were randomised to conventional shampooing with Allermyl
temporary.
shampoo (which contains vitamin E, essential fatty acids and
piroctone); or Allermyl shampoo in a whirlpool bath; or wa-
In a double-blind, placebo-controlled trial, 27 dogs aller-
ter alone in a whirlpool for 20 minutes (it was expected that
gic dogs with a history of mild-to-moderate pruritus were
the bubbles in the whirlpool would lift the hairs and help the
randomised to twice-weekly shampooing over 4 weeks with
shampoo get to the skin).3 Owner-assessed pruritus scores
DermaTopic (a German brand of shampoo containing chlo-
(on a scale of 0–10) 24 hours after shampooing improved by
rhexidine, piroctone and chitosan) or placebo (a shampoo
more than half (from an average baseline score of 4) in 25%
vehicle without active ingredients).4 Four dogs were with-
of dogs with conventional shampooing; this increased to 39%
drawn from the placebo group because of skin reactions
of dogs who were shampooed in a whirlpool bath. However,
and one from the treatment group because of lack of effect.
the same degree of improvement was seen in 22% of dogs
There was a significant reduction in owner-evaluated pruri-
who had a whirlpool bath without shampooing. Few dogs
tus in both groups, but no significant difference between the
had a more than 90% improvement in pruritus (16% with
two groups.
shampoo plus whirlpool; 6% with conventional shampoo;
The results of these studies suggest that much of the benefit on pruritus from bathing might come from the action of washing the dog.
3. Löflath A et al. The efficacy
of a commercial shampoo and
whirlpooling in the treatment
of canine pruritus – a
double-blinded, ramdomized,
placebo-controlled study. Vet
Dermatol. 2007; 18: 427-31
4. Schilling J, Mueller RS.
Double-blinded, placebocontrolled study to evaluate
an antipruritic shampoo for
dogs with allergic pruritus.
Vet Rec 2012; 171: 97.
February 2015
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Malassezia
In a single-blind trial, 67 dogs with dermatitis associated with
transient adverse effects (acute pododermatitis, exfoliation
Malassezia overgrowth were randomised to 2% micona-
and scaling and increased pruritus vs. none with miconazole/
zole/2% chlorhexidine shampoo (Malaseb) twice weekly for
chlorhexidine). With either shampoo, 28 days’ treatment was
up to 6 weeks, or 3% chlorhexidine shampoo (Microbex)
required for full efficacy in most dogs.
three times weekly for 2 weeks and then if needed twice
weekly for 2 weeks, and then if needed weekly for 2 more
In a double-blind randomised trial involving 33 Basset
weeks.5 More dogs in the 3% chlorhexidine group (5 vs. 1)
hounds with dermatitis and Malassezia overgrowth, sham-
were withdrawn from the trial because of lack of compli-
pooing every 3 days for three weeks with 2% miconazole/2%
ance to the treatment. There were similarly large reductions
chlorhexidine was significantly more effective than selenium
in Malassezia counts and clinical scores in the two groups
sulphide 0.25% in reducing Malassezia and bacterial counts
(no statistically significant differences between the groups).
and overall clinical severity, including pruritus, erythema and
Four dogs in the 3% chlorhexidine group showed minor
exudation.6
Bacterial overgrowth
In a single-blind randomised controlled trial, 40 dogs with
the proportion of dogs with at least 90% reduction in bacte-
clinical signs and cytological findings compatible with bacte-
rial counts (61% with chlorhexidine vs. 56% with benzoyl
rial overgrowth were treated twice weekly with 3% chlo-
peroxide) or time to cytological cure. Clinical score re-
rhexidine shampoo or 2.5% benzoyl peroxide shampoo and
duced by at least 85% in 39% of dogs with chlorhexidine vs.
evaluated for up to 6 weeks until cytological cure.7 There
19% with benzoyl peroxide (no significant difference).
was no significant difference between the two treatments in
5. Maynard L et al.
Comparison of two shampoos
for the treatment of canine
Malassezia dermatitis: a
randomised controlled trial. J
Small Animal Pract 2011; 52:
566–72.
6. Bond R et al. Comparison
of two shampoos for
treatment of Malassezia
pachydermatis-associated
seborrhoeic dermatitis in
basset hounds. J Small An
Pract 1995; 36: 99-104.
7. Viaud et al. Comparison
of two shampoos as sole
treatment for canine bacterial
overgrowth syndrome. Vet
Record 2012; doi: 10.1136/
vr.100643.
February 2015
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Dermatology guidelines
The current international evidence-based guidelines on man-
soothing effect to the skin, the physical removal of surface
aging canine atopic dermatitis8 (due to be updated later this
allergens and microbes and an increase in skin hydration,
year) recommend bathing with a non-irritating shampoo for
with no evidence of superiority of any particular shampoo
improvement of skin and coat hygiene in the treatment of
or protocol. The guidelines state that shampoos containing
acute flares of atopic dermatitis as part of a multimodal ap-
antibacterial and/or anti-fungal agents are appropriate for
proach.8 For dogs with chronic canine atopic dermatitis, they
skin infections, and antiseborrhoeic shampoos are indicated
recommend weekly bathing with a non-irritating shampoo
if the skin is greasy or scaly.8
and lukewarm water for improving the skin and coat hygiene.
The guidelines state that the likely benefit is from a direct
Using shampoos in practice
Shampooing is laborious and time-consuming: it is needed
turisers might alleviate any skin dryness that occurs after
two or three times a week for at least 3 to 4 weeks for the
baths.8 Owners should be reminded to report any exacer-
treatment of bacterial or fungal infection,5,6,7 and weekly for
bation of the skin disease after bathing so that a different
chronic atopic dermatitis.3,8 Occasionally there may be local
shampoo might be used. It is reasonable to limit the choice
adverse reactions to a shampoo and some specialists recom-
of shampoos in a practice to a small range that includes
mend a test wash on a small area of the dog when first using
alternatives if the first choice is ineffective or not tolerated.
a shampoo. Some shampoos can have a drying effect. Mois-
3. Löflath A et al. The efficacy
of a commercial shampoo and
whirlpooling in the treatment
of canine pruritus – a
double-blinded, ramdomized,
placebo-controlled study. Vet
Dermatol. 2007; 18: 427-31
http://onlinelibrary.wiley.
com/doi/10.1111/j.13653164.2010.00889.x/pdf
5. Maynard L et al.
Comparison of two shampoos
for the treatment of canine
Malassezia dermatitis: a
randomised controlled trial. J
Small Animal Pract 2011; 52:
566–72.
6. Bond R et al. Comparison
of two shampoos for
treatment of Malassezia
pachydermatis-associated
seborrhoeic dermatitis in
basset hounds. J Small An
Pract 1995; 36: 99-104.
7. Viaud et al. Comparison
of two shampoos as sole
treatment for canine bacterial
overgrowth syndrome. Vet
Record 2012; doi: 10.1136/
vr.100643.
8. Olivry T et al. Treatment
of canine atopic dermatitis:
2010 clinical practice
guidelines from the
International Task Force on
Canine Atopic Dermatitis. Vet
Dermatol 2010; 21: 233–48.
February 2015
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What’s available?
‘Medicated’ shampoos for dogs
Antimicrobial
Malaseb (chlorhexidine 2%, miconazole
2%) (POM-V, for treatment and control
of seborrhoeic dermatitis associated with
Malassezia and/or Staphylococcus)
Micobex (chlorhexidine 3%) (POM-V,
for treatment of Malassezia surface
proliferation and control of associated
clinical signs)
Emollient
Allermyl (vitamin E, essential fatty acids,
piroctone)
Canac Medicated (aloe vera)
Coatex Aloe and Oatmeal (aloe vera,
oatmeal)
Epi-Soothe (colloidal oatmeal, glycerine,
chitosanide, ‘spherulites’)
Clearcoat ketoconazole 1%
Etiderm (ethyl lactate, benzalkonium
chloride, chitosanide ‘spherulites’)
Etiderm (ethyl lactate, benzalkonium
chloride, chitosanide, ‘spherulites’)
Sebocalm (urea, glycerine)
Coatex (chloroxylenol, salicylic acid,
sodium thiosulphate)
Malacetic (acetic acid 2%, boric acid 2%)
Dermocanis High GLA (essential fatty
acids)
DermAllay Oatmeal (oatmeal)
DermAllay Sensitive (coconut)
Pet Head Life’s an Itch (oatmeal, aloe
vera)
Vet solution Aloe and Oatmeal
Wahl Oatmeal Essence (coconut,
almond oil, oatmeal)
Anti-scale
Seleen (selenium sulphide 1%) (AVM-GSL,
for treating seborrhoeic dermatitis)
Coatex (chloroxylenol, salicylic acid,
sodium thiosulphate)
Sebomild P (ammonium lactate,
piroctone, essential oil, chitosanide,
‘spherulites’);
Zincoseb (colloidal sulphur, salicylic acid,
zinc gluconate)
February 2015
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Contact
Conclusion
Veterinary Prescriber
Shampoos can be useful in the management of certain canine skin diseases, although their use is laborious and time-consuming. The active ingredients in some ‘medicated’ shampoos make them suited to certain uses (e.g. antifungal shampoos for
Malassezia overgrowth). However, there is little formal evidence assessing the effects of shampoos in the treatment of canine skin diseases. In atopic dermatitis, the benefit of shampooing appears to come mainly from the act of washing the dog.
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