February 2015 veterinaryprescriber@gmail.com www.veterinaryprescriber.com 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
What s in shampoos? The cleansing action of shampoos comes from surfactants, which help remove dirt and grease. 1 Soap, the original the surfactant in shampoos, tends to irritate the skin due to its alkalinity, and has been replaced in modern shampoos by synthetic surfactants. 1 Shampoos will often contain a mixture of different surfactants together with conditioners (e.g. oils, silicones, chitosanide), other additives (e.g. moisturisers, stabilisers, fragrance and colour) and active ingredients for the management of specific problems such as Malassezia or bacterial overgrowth, scaling and flea infestation (e.g. miconazole, chlorhexidine, salicylic acid, permethrin). 1. Trueb RM. Shampoos: ingredients, efficacy and adverse effects. JDDG 2007; 5: 356 65. Active ingredients in shampoos Antibacterial: acetic acid; boric acid; chlorhexidine; ethyl lactate; piroctone. Reduction of scale: zinc gluconate; ammonium lactate; salicylic acid; chitosanide; selenium sulphide. Antifungal: acetic acid; boric acid; chlorhexidine; ketoconazole; miconazole. Emollient: aloe; colloidal oatmeal; chitosanide; essential fatty acids; glycerine; urea. Insecticide. Several insecticidal shampoos are available on general sale (legal category AVM-GSL). They contain permethrin alone, or pyrethrins + piperonyl butoxide. As they have no residual effect they have a limited role in the management of flea infestations.
Indications and claims A few shampoos are licensed as medicines and have specific licensed indications (see What s available below). These are prescription-only (POM-V) products containing chlorhexidine alone or together with miconazole, for the treatment of bacterial or fungal infections; a shampoo containing selenium sulphide for the treatment of seborrhoeic dermatitis (AVM-GSL); and the insecticidal shampoos mentioned above (AVM-GSL). Most shampoos are not licensed as medicines but labels commonly include a description to indicate how they may be used. For example, for dry scaly skin, for itchy dogs. Other are variously described on the labels as soothing, microbial balancing, hypoallergenic, soap free, exfoliating. 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.
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 history of allergic or idiopathic pruritus for at least 4 weeks were randomised to conventional shampooing with Allermyl shampoo (which contains vitamin E, essential fatty acids and piroctone); or Allermyl shampoo in a whirlpool bath; or water alone in a whirlpool for 20 minutes (it was expected that the bubbles in the whirlpool would lift the hairs and help the shampoo get to the skin). 3 Owner-assessed pruritus scores (on a scale of 0 10) 24 hours after shampooing improved by more than half (from an average baseline score of 4) in 25% of dogs with conventional shampooing; this increased to 39% of dogs who were shampooed in a whirlpool bath. However, the same degree of improvement was seen in 22% of dogs who had a whirlpool bath without shampooing. Few dogs had a more than 90% improvement in pruritus (16% with shampoo plus whirlpool; 6% with conventional shampoo; none with water alone). Pruritus scores were unchanged by the end of the trial showing that the effect of shampooing is temporary. In a double-blind, placebo-controlled trial, 27 dogs allergic dogs with a history of mild-to-moderate pruritus were randomised to twice-weekly shampooing over 4 weeks with DermaTopic (a German brand of shampoo containing chlorhexidine, piroctone and chitosan) or placebo (a shampoo vehicle without active ingredients). 4 Four dogs were withdrawn from the placebo group because of skin reactions and one from the treatment group because of lack of effect. There was a significant reduction in owner-evaluated pruritus in both groups, but no significant difference between the two groups. 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. The results of these studies suggest that much of the benefit on pruritus from bathing might come from the action of washing the dog.
Malassezia In a single-blind trial, 67 dogs with dermatitis associated with Malassezia overgrowth were randomised to 2% miconazole/2% chlorhexidine shampoo (Malaseb) twice weekly for up to 6 weeks, or 3% chlorhexidine shampoo (Microbex) three times weekly for 2 weeks and then if needed twice weekly for 2 weeks, and then if needed weekly for 2 more weeks. 5 More dogs in the 3% chlorhexidine group (5 vs. 1) were withdrawn from the trial because of lack of compliance to the treatment. There were similarly large reductions in Malassezia counts and clinical scores in the two groups (no statistically significant differences between the groups). Four dogs in the 3% chlorhexidine group showed minor Bacterial overgrowth In a single-blind randomised controlled trial, 40 dogs with clinical signs and cytological findings compatible with bacterial overgrowth were treated twice weekly with 3% chlorhexidine shampoo or 2.5% benzoyl peroxide shampoo and evaluated for up to 6 weeks until cytological cure. 7 There was no significant difference between the two treatments in transient adverse effects (acute pododermatitis, exfoliation and scaling and increased pruritus vs. none with miconazole/ chlorhexidine). With either shampoo, 28 days treatment was required for full efficacy in most dogs. In a double-blind randomised trial involving 33 Basset hounds with dermatitis and Malassezia overgrowth, shampooing every 3 days for three weeks with 2% miconazole/2% chlorhexidine was significantly more effective than selenium sulphide 0.25% in reducing Malassezia and bacterial counts and overall clinical severity, including pruritus, erythema and exudation. 6 the proportion of dogs with at least 90% reduction in bacterial counts (61% with chlorhexidine vs. 56% with benzoyl peroxide) or time to cytological cure. Clinical score reduced by at least 85% in 39% of dogs with chlorhexidine vs. 19% with benzoyl peroxide (no significant difference). 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.
Dermatology guidelines The current international evidence-based guidelines on managing canine atopic dermatitis 8 (due to be updated later this year) recommend bathing with a non-irritating shampoo for improvement of skin and coat hygiene in the treatment of acute flares of atopic dermatitis as part of a multimodal approach. 8 For dogs with chronic canine atopic dermatitis, they recommend weekly bathing with a non-irritating shampoo 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 two or three times a week for at least 3 to 4 weeks for the treatment of bacterial or fungal infection, 5,6,7 and weekly for chronic atopic dermatitis. 3,8 Occasionally there may be local adverse reactions to a shampoo and some specialists recommend a test wash on a small area of the dog when first using a shampoo. Some shampoos can have a drying effect. Mois- soothing effect to the skin, the physical removal of surface allergens and microbes and an increase in skin hydration, with no evidence of superiority of any particular shampoo or protocol. The guidelines state that shampoos containing antibacterial and/or anti-fungal agents are appropriate for skin infections, and antiseborrhoeic shampoos are indicated if the skin is greasy or scaly. 8 turisers might alleviate any skin dryness that occurs after baths. 8 Owners should be reminded to report any exacerbation of the skin disease after bathing so that a different shampoo might be used. It is reasonable to limit the choice of shampoos in a practice to a small range that includes alternatives if the first choice is ineffective or not tolerated. 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.1365-3164.2010.00889.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.
What s available? Medicated shampoos for dogs Antimicrobial Emollient Anti-scale 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) 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 ) 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 ); Clearcoat ketoconazole 1% Etiderm (ethyl lactate, benzalkonium chloride, chitosanide, spherulites ) Coatex (chloroxylenol, salicylic acid, sodium thiosulphate) Malacetic (acetic acid 2%, boric acid 2%) Etiderm (ethyl lactate, benzalkonium chloride, chitosanide spherulites ) Sebocalm (urea, glycerine) 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) Zincoseb (colloidal sulphur, salicylic acid, zinc gluconate)
Conclusion 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. Contact Veterinary Prescriber to give feedback on this article or get involved as a writer, commentator or editorial consultant. Use the mail link below to get in touch. copyright 2014 Mixolydian Publications Limited. All rights reserved.