Your Dog's Skin and Coat

If you live with a dog for very long, you are familiar with the abundant fur coat that seems to fall off whenever you wear a color that contrasts most with the fur color. Did you ever wonder about the function of a dog's fur? What about the structure of the skin and coat?

Chinese crested dog
Dog's skin and fur provide protection and sensory input.

The Integumentary System

Your dog's integumentary system is made up of skin, fur, claws, pads, and skin glands. The system covers the dog's body, providing protection to the muscles, skeleton, and those important internal organs. The skin is the largest organ in the body and serves important sensory and protective functions.

In addition to allowing the dog to feel touch, pressure, temperature, pain, and vibrations, the skin prevents the dog's tissues from drying out or being invaded by germs. The skin also produces vitamin D which is vital in allowing calcium to be absorbed from the dog's diet to keep bones healthy.

The skin glands associated with hair follicles release secretions which moisten the skin and provide some degree of waterproofing. Dogs like retrievers who were bred to work in water have a high oil level on their fur to make water run off the guard hairs rather than soaking into the skin. Finally, pheromones that allow one dog to identify another are released from skin glands.

Fur provides insulation from the winter's cold, as well as from the summer's intense heat. Contrary to popular belief, shaving a dog in the summer will not make him cooler. The dog's fur catches air beneath it, providing a layer of insulation to prevent the dog from becoming over-heated during hot weather. Because the only sweat glands on a dog are on the pads of his feet, this alternative cooling mechanism serves an important protective function.

Whiskers are a special kind of hair, concentrated on the dog's face. Whenever anything brushes against a dog's whiskers, the dog will close his eyes, turn his head, back up, shake his head, or paw at his face. Whiskers should never be trimmed because they serve an important protective function for the dog's eyes and nose.

Canine Skin and Hair Structure

The epidermis is a tough outer layer of the skin, made up of keratin, which is shed from the body fairly regularly. Shed skin from you and your animals makes up the bulk of the dust in your home. Under the epidermis is the dermis, composed of skin cells that are forming and will rise to the surface to be shed in a continuous cycle. In addition to budding skin cells, the dermis contains a rich network of blood vessels, nerves, hair follicles, sweat glands, and oil glands. Under the dermis is a supporting layer of fat and muscle.

Your dog's skin may have areas of dark coloration, caused by melanin. Just as in humans, melanin in the skin protects the dog from the harmful UV rays of the sun. The dog's fur is also protective, and dogs with sparse fur are especially susceptible to sunburn.

Growing from the hair follicles of the dermis are two types of hair. Guard hairs are long and thick, growing one hair per follicle. Up to 15 secondary or under-hairs can grow from each follicle as well. The small under-hairs give the coat its softness and provide insulation for the dog.

Dog breeds that don't shed so much have a high density of hair follicles, meaning they have more guard hairs per square inch. In addition, they have a low number of under-hairs associated with each follicle. By contrast, dogs like German Shepherds have fewer follicles, but a high number of under-hairs associated with each one. These dogs "blow" their coats with every season change, losing clumps of under-hair at a time.

Shedding is not actually controlled by the outside temperature, but rather by the length of time between sun-up and sun-down. In fact, dogs who live outdoors are likely to shed more during changes of season, while indoor dogs tend to shed year-round due to their exposure to artificial light sources. Dogs also shed after anesthesia, and female dog families may see an increase in shedding after heat cycles and whelping.

Shedding may cause your dog's skin to be itchy and uncomfortable. You can help reduce the discomfort by daily brushing to remove loose hair.

Coat of Many Colors

The color of a dog's coat is determined by at least ten different gene sites. These genes control color, distribution of colors, intensity of color, masking on the face, patterning of the coat, and changes that occur as the dog ages. In addition, the dog's guard hairs may be of a totally different color than his undercoat.

Closeup of dog's fur
Coat color is determined by genes.

In some breeds, there is genetic material for only one color; others carry the genes for different shades of the same color, others for two colors only, while others have genetic material to provide a wide palette of color and pattern variations. Common examples include the West Highland White Terrier, which is always white, the Golden Retriever, which comes in many shades of gold, the Rottweiler that comes in black and tan, and the Great Dane, which can come in nearly any color or pattern.

Skin Problems

Your dog's skin can be damaged by objects that cut or puncture it, by parasites, by infections, and by other irritants. When your dog receives a cut or a puncture wound, one of your first considerations is likely to be whether or not to seek veterinary care. In general, if a cut is bigger than one-inch long or one-inch deep, it will need to be stitched. Puncture wounds, on the other hand, are not generally stitched closed. As long as you can control the blood loss, small cuts do not generally need professional attention. Simply apply pressure to stop the bleeding, then cleanse the area with bottled water or saline, apply an antibiotic ointment, and cover with a dressing to keep it clean.

Parasites such as ringworm, mange mites, fleas, and ticks can cause diseases even beyond the skin layer. Ringworm infections can even be passed to the human family, as well. If you suspect your dog has one of these infections, consult the dog den article library for in-depth articles on each of these topics.

Hot spots are a common affliction in some breeds of dogs. Injuries, allergies, parasites, and even stress can cause a dog to start licking and scratching at one particular area. The skin begins to break down, become inflamed, and produce pus as it becomes infected. The area is extremely painful and the red area will spread very rapidly. Your dog may be very agitated when you try to examine the area, so be sure to muzzle your dog or have someone hold his or her head while you provide treatment.

If there is hair matted over the hot spot, the first line of treatment is to shave it off. Clean the area thoroughly with cool water and apply cool compresses several times each day. Black or green tea bag compresses can be used to help dry out the area, and your vet may prescribe a drying ointment to be applied to the sore. Aluminum acetate solutions such as Domeboro's or Burow's may be helpful drying agents as well.

Contact dermatitis produces itchy red bumps and inflammation when your dog's skin comes up against certain common chemicals or allergic agents. Shampoo, house cleaning chemicals, and even medications can cause your dog's skin to break out in blisters, crusting, and moist spots which then set up a breeding ground for secondary infectious agents or even for hot spots.

Your dog's coat as an indicator of health

One of the earliest indicators you may have of a problem with your dog's health may be a problem with his coat. For example, allergies can cause the dog's hair to fall out. Thyroid problems and other hormone imbalances can cause dry, brittle hair. Poor nutrition, especially insufficient fat content, can cause the coat to become dull and dry.

Caring for your dog's coat

One of the most important things you can do to keep your dog's coat healthy is to provide a healthy diet with adequate protein and fat. Next, brush your dog as often as possible, at least once a week. Brushing not only removes hair that would otherwise end up on your furniture, it also provides emotional bonding time between you and your dog, gives you a chance to inspect your dog for any health problems, and keeps your dog's coat shiny and healthy. Bathing is important when your dog is dirty, but too much time in the bathtub can cause your dog's skin to dry out.


Leave a comment on this article here!


Jeff Weber [email protected]
Wow! This article is very impressive and educational. I always thought my dog's shedding cycle was based on temperature. It also was fascinating to me to learn about the guard hair and under hair. I had two Siberian Huskies and grooming was a full time job under normal circumstances and I thought I was going to have to hire help from the temp service when they would blow their coat. I really enjoyed this information and have a better understanding about my pets skin and coat health. Thanks a million Jeff Weber
[email protected]
My Pom has large scale of dandriff on her back, she is on theroid meds and it has not helped. She first lost hair on her rump and now has the skin shedding and hair thinning on her back. What do I do. She is on Imas dry dog food. How about fish oil? She doesn't bite or scratch herself. Not a hot spot or mannage! Help, Please
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