Dog Owner's Home Veterinary Handbook.pdf - Mr. Walnuts

C h a p t e r
THE SKIN AND COAT
Skin disease is a common problem in dogs. The condition of the skin can also
tell you a great deal about your dog’s general health. A dog’s skin is thinner
and more sensitive to injury than human skin. It is easily damaged by rough
handling with the wrong type of grooming equipment, and once the surface of
the skin is broken and disturbed by trauma or some other disorder, the condition
tends to spread rather easily and become a major problem.
The outer layer of skin is the epidermis, a scaly layer that varies in thickness
over different parts of the body. For example, it is thick and tough over
the nose and foot pads, and thin and most susceptible to injury in the creases
of the groin and armpits.
The layer beneath the epidermis is the dermis. The dermis gives rise to the
skin appendages: hair follicles, sebaceous glands, nails, and sweat glands.
Sweat glands are found only in the foot pads of dogs.
Hair follicles produce three types of hair. Primary hair is exemplified by the
long guard hair that makes up the top coat. Generally, each guard hair grows
from its own follicle, but in some breeds more than one hair may grow from a
single follicle. Muscles connected to the root of each guard hair enable the
hair to stand erect, as happens when a dog raises her hackles.
Within each guard hair follicle is a cluster of accessory hair that composes
the undercoat. The function of the undercoat is to provide warmth and protection.
Whiskers and eyelashes make up a third type of hair, which is modified
to serve the sense of touch.
Sebaceous glands are located in the dermis, and are linked to the hair follicles.
Sebaceous glands secrete an oily substance called sebum, which collects
in the hair follicles and coats each strand of hair. This adds shine and, more
important, enables the hair to shed water. Water-going breeds depend upon
sebum to waterproof their coats. Sebum is also responsible for the characteristic
doggy odor apparent in some dogs with oily coats.
The color of a dog’s skin can vary from pink to light brown, or it may be
dark with patches of black. The dark pigment in the skin is called melanin. It
is produced by cells in the dermis called melanocytes.
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