DERMATOLOGY
Shaping the future of animal health
Shampoo Therapy
Veterinary Dermatology
Dr Heidi Schroeder, BVSc MMedVet(Med)
Small Animal Physician
Willow Park Small Animal
Medicine Specialist Hospital,
Willow Glen, Pretoria Pretoria,
(012) 813 8009
[email protected]
INTRODUCTION
The use of therapeutic shampoos for the treatment
of skin diseases has become an integral part of the
treatment regimes of Veterinary Dermatology. Veterinarians should know details about the composition of
shampoos, their mechanism of action, and when and
how to use them. This will help in instructing owners
and obtaining the best treatment results.
A shampoo is an aqueous solution, with added surfactants, cleansing agents and various therapeutic
and/or cosmetic agents. In animals, the hair coat penetrating and cleansing effect of a shampoo has a great
advantage over the use of other topical formulations
such as creams and ointments. The pH of a dog’s skin
is different from that of a human. The pH of canine
skin is 7.5 compared to 5.5 for human skin. Due to
the alkalinity of a dog’s skin, it provides a favourable
environment for bacterial growth. Many skin diseases
in small animals have a wide spread to generalised
distribution. Shampoos are particularly useful for the
treatment or management of such disorders.
GENERAL PRINCIPLES
Medicated shampoos work in more than one way.
They allow application of specific therapeutic molecules to skin and hair, restore normal structure and
function of the skin and cleanse the skin and hair of
microbes and parasites, allergens and other harmful
material. In this way they enable many specific and
non-specific dermatological disorders to be effectively treated, managed or prevented.
The therapeutic molecules need to be absorbed
and to penetrate to the deeper layers of the skin in
high enough concentrations in order to achieve a
therapeutic effect. The time needed to achieve this,
is known as the contact time. Contact time can be
defined as the time interval between the end of ap-
plying the shampoo and rinsing it off. Contact time is
usually between 5 and 15 minutes. In most shampoos
the active ingredients are removed when the shampoo is rinsed off. To be fully effective many medicated
shampoos have to be repeated very frequently. This
may lead to dehydration of the stratum corneum and
loss of the protective barrier function and often leads
to disappointing results. The correct contact time and
correct frequency of the shampoo therapy are therefore crucial for success.
SHAMPOO THERAPY FOR SPECIFIC
DERMATOLOGICAL DISORDERS
There are 6 categories of dermatological disorders
which will be discussed with special focus on shampoo treatment of these disorders:
1. Keratoseborrhoeic disorders (KSD)
Keratoseborrheic disorders (KSDs) are those that alter
the surface appearance of the skin. The epidermis of
animals is constantly being replaced by new cells. The
normal epidermal cell renewal time is approximately
22 days. Despite this high turnover rate, the epidermis
maintains its normal thickness, has a barely perceptible
surface keratin layer, and loses its dead cells invisibly
to the environment. If the delicate balance between
cell death and renewal is altered, the epidermal thickness changes, the stratum corneum becomes noticeable, and the normally invisible sloughed cells of the
stratum corneum become obvious.
Keratoseborrheic disorders (KSD) are characterized by
scaling, crusting, greasy or dry skin and alopecia and
can be primary or secondary. Generally the primary
KSDs are hereditary and are associated with a primary keratinisation defect. They usually manifest clinically by excess scale formation in which the primary
pathophysiology involves a defect in the keratinising
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