What’s a shampoo?
Shampoo is an aqueous or semisolid preparation containing various ingredients like surfactants, cleansing agents and various other therapeutic and/or cosmetic agents used to remove surface grease, dirt and skin debris from the hair shaft and scalp without adversely affecting the hair, scalp or health of the user. Shampooing is one of the widely used methods in keeping the dog clean and healthy.
Principles of shampooing
Objective of shampooing is to cleanse the skin and hair coat. Soil or dirt basically consists of soluble, oily and insoluble particulate components. Surfactant (sodium lauryl sulfate) present in the shampoo reduces the surface tension of the water and thereby allows full contact between water and soluble soil. This facilitates the removal of soluble soils by aqueous medium. Detergent present in the shampoo displaces oily soil by a process known as roll up and thereby removes them from skin and haircoat. Surfactant molecules get adsorbed onto the hair fibre and thereby create an electrostatic repulsion force between insoluble soil particles and hair fibre. This electrostatic repulsion force removes insoluble soil particles from skin and haircoat.
Characteristics of a shampoo
- It should be able to remove sebum and atmospheric pollutants from the hair and scalp.
- It should be able to remove the residues of previously applied hair treatments, for example, hair sprays.
- It should be able to deliver an optimum level of foam to satisfy the expectation of the user.
- It should be able to provide the conditioning effect to the hair coat.
- It should be able to perform as a vehicle for the deposition of beneficial materials onto the hair and scalp.
- It should be able to be non-toxic and non-irritating to the hair and the scalp.
- It should be able to be non-damaging to the tissues of the eye if inadvertently splashed.
Classification of shampoos
Shampoos are usually classified according to their purpose of usage, for example, conditioning shampoo, cosmetic shampoo, antifungal shampoo, antibacterial shampoo, anti-dandruff shampoo, etc.
Ingredients of shampoo
Various ingredients like surfactants, cleansing agents, emollients, emulsifiers, antimicrobials are included in the shampoo and their incorporation depends on the purpose of use. For example, antimicrobials, antiseborrheic agents are included in medicated shampoos. Whereas humectants, emollients, emulsifiers are principle ingredients of cosmetic shampoos. The table on page 30 will help in understanding incorpation of certain ingredients and their use in different conditions.
General guidelines for the selection of shampoo
- In general, human shampoo or conditioners are not recommended for use in dogs.
- Examine your dog before bathing and determine if there are special needs. It will make the shampoo selection process much easier.
- Use only dog-specific shampoo that caters exclusively to your dog’s skin and fur needs.
- l Ideally, a shampoo possessing both cleansing and therapeutical properties should be applied twice.
- Don’t shampoo sick and ailing animals.
Shampoos for different dermatological disorders
Shampooing is one of the most popular and effective ways of treating dermatological affections.
- Pyoderma: Shampooing plays an important supportive role in the treatment of pyoderma. Chlorhexidine, povidone-iodine, benzoyl peroxide and ethyl lactate are the principle ingredients of antibacterial shampoos. Shampooing plays its role by decreasing cutaneous bacterial population and removing the surface tissue debris and thereby allowing the direct contact of the active ingredient with the organism and promoting the drainage. Usually shampooing is used along with systemic antibiotics in the treatment of pyoderma. But certain cases of surface pyoderma will respond to the topical antibacterial shampoos alone. In cases of deep pyoderma clipping of hair facilitates the contact of the product to the lesions. Frequency of shampooing depends on the severity of the lesions. Severe the lesions, more frequent will be the application.
- Keratoseborrhoeic disorders: Shampoos containing keratomodulating agents (salicylic acid, coal tar, selenium disulphide, ethyl lactate) and antiseborrhoeic agents (sulphur, benzoyl peroxide) are used. Initially shampooing will be done 2 to 3 times weekly; with improvement in condition frequency of application can be reduced gradually. Long-haired dogs should be clipped. Clipping leads to more effective application and better distribution of the active ingredient. Efficacy of treatment should be monitored frequently.
- Fungal diseases: Shampoos containing miconazole, ketaconazole and chlorhexidine are used to treat fungal skin disorders. Antimycotic shampoos are used as an adjunctive therapy for dermatophytosis and Malassezia dermatitis. They limit contagiosity in case of dermatophytosis but are not effective in treating it when used alone. They are often used with systemic antifungals. Keratomodulating shampoos are beneficial in removing infected scales and crusts. They are used along with topical antifungals when there is keratoseborrhoeic disorder. Topical antifungal shampoos or lotions are preferable for extensive lesions.
- Allergic diseases: Shampoos containing antipruritic agents like 1 percent hydrocortisone, 0.01 percent fluocinolone, 2 percent diphenhydramine, 1 percent pramoxine or colloidal oatmeal are used in allergic dermatitis. Antipruritic shampoos exert their beneficial effect by washing out the allergens from the skin and rehydrating the dry skin. Antipruritic shampoos should be used more frequently at least twice a week in the beginning of therapy. As antipruritic shampoos are rarely effective as sole therapy they are generally considered as adjunctive treatments to canine atopic dermatitis.
- Parasitic diseases: Shampoos containing organochlorines, natural pyrethrins or synthetic pyrethroids are used as antiparasitic shampoos. As antiparasitic shampoos are rinsed off quickly and cannot act during a sufficient time, they are considered to be not efficacious as other formulations like sprays, pump-sprays, powders, spot-ons and line-ons.
Shampoos containing benzoyl peroxide are recommended in the treatment of demodicosis because of their degreasing and follicular flushing effect. Many parasitic diseases like scabies, cheyletiellosis and flea allergy dermatitis will cause a keratoseborrhoeic disorder and the affected animals will benefit from application of keratomodulating shampoos.
Once you know your dog’s coat condition, use an appropriate shampoo for him.
Tips for shampooing your pooch
- Having another person with you to hold the dog should make the job easier.
- Use of a shower head will help removal of surface debris and dirt, as well as thoroughly wetting the coat and skin. A sponge may also be useful for harder-to-reach areas (such as between the toes).
- If using a bath tub, do not leave the plug in, as this may lead to dilution of the shampoo when your dog is standing in the water.
- Ensure that the water is lukewarm. If the water is too cold, your dog may be uncomfortable and reluctant to bathe in future. If the water is too hot, it can increase the dog’s desire to scratch.
- l The optimum skin contact time for shampoo is 10 minutes. Timing should start as soon as the dog has been lathered. Be careful of the eyes, if shampoo gets into the eyes, bathe them with large amounts of clean, lukewarm water.
- After rinsing him properly with water, hand dry with a towel. Do not use a hairdrye, as heating of the skin surface may lead to itching and can damage the hair and upper skin layers.
- Do not allow the animal to lick himself during the shampooing and rinsing or before the dog is dried.
- Take care to avoid the animal inhaling the product or getting it into the nose, mouth or eyes during shampooing.
(Dr Priyanka is Assistant Professor, Department of Teaching Veterinary Clinical Complex, Veterinary College, Hassan, Karnataka while Dr Vijay Kumar M is Assistant Professor, Department of Pharmacology and Toxicology Veterinary College, KVAFSU, Bidar, Karnataka).