Skin and Hair:
What Every Pet Parent Should Know

Posted - July 27, 2021

By Patricia Thomblison, DVM, MS

Did you know the skin is the largest organ on a cat or dog, comprising of 12 to 24% of an animal’s body weight? With a few exceptions, most cats and dogs also have haircoats or fur covering most of their body. There are many functions of skin and hair, and one of the first things a veterinarian will look at when examining an animal is because the skin and hair can give an indication of a pet’s overall health. Knowing some facts about the skin and hair can help you better care for your pet.


The skin has several functions. These include providing an environmental barrier from chemical, physical, solar, and microbial agents and participating in temperature control.  The skin also contains sensory nerves to detect touch, surface temperature, and pain. The thickness of the skin varies with species, breed, and body location. It is also the thickest on the back and dorsal neck and thins toward the abdomen.


The skin has three layers. The outer layer, the epidermis, is the thinnest, but the most metabolically active. The lifespan of epithelial cells is approximately 22 days, which is shorter than the 28-day lifespan of epithelial cells in people. The middle layer is the thickest and contains sebaceous glands and hair follicles. This layer is responsible for tensile strength and wound healing. There are also muscles which can make the hair “stand on end” The hypodermis or subcutis is the deepest layer of skin and has fat cells which provide insulation and protection against impact.


Hair comes in a wide range of colors and styles. Hair functions as insulation for environmental changes of hot and cold as well as a cushion against physical stress. Whiskers are specialized hairs that send sensory messages to the brain. Hair has different periods of growth: an active period of growth (anagen), a resting phase (telogen) and a transition phase (catagen). Most dogs stay primarily in the resting stage which means hairs are maintained for a period of time before shedding. Hair grows in cycles which are regulated by seasonal and environmental changes. Some dogs shed more in the spring but less in the winter. Dogs that are kept indoors tend to shed all year long to some extent.


The skin and hair provide a picture of the overall health of the animal. The hair might be dull or dry, the skin flaky or greasy, or the hair may be thinning, and all can be caused by different diseases, diet deficiencies, etc. One common sign of unhealthy skin is itchiness but finding the cause can be complicated.

The reason for itching can have multiple causes and some can occur together.  Itching is just a sign. It’s not a diagnosis but a sign that should not be ignored. The skin is limited in the way it can respond with itching being the typical response. The most common causes include parasites, infections, and allergies. Even if the initial skin disease does not cause itching, secondary infections can lead to itching and scratching. It can become a vicious cycle of itching, scratching, irritating the skin, and more itching and scratching.

It is not just itching and scratching that can indicate unhealthy skin. There are also behaviors such as foot chewing and biting and excessive grooming. Here are other signs of unhealthy skin to be on the alert:

  • Hair loss
  • Unpleasant odor
  • Skin redness
  • Sores, pustules, and hot spots


As a pet parent you can do your part to help maintain healthy skin and haircoat. The following list includes some things you can do:

  • Feed a nutritious diet.
  • Protect from fleas and ticks.
  • Speak to your veterinarian about nutritional supplements.
  • Brush regularly to remove excess hair and distribute skin oils.
  • Check frequently for lumps, bumps, cuts, scratches, or abrasions.
  • Select a shampoo and conditioner specifically designed for your pet.

You can help your pet by providing regular bathing to wash away environmental irritants and support the natural barrier and to maintain the health and hydration of the skin. Products such as veterinarian-recommended ZYMOX® Shampoo and ZYMOX Leave-On Conditioner can calm and care for inflamed or infected skin without the use of harsh chemicals that might further irritate the skin.  The ZYMOX line of skin care products contain the patented LP3 Enzyme System to manage skin conditions without antibiotics. This line also includes the ZYMOX Topical Cream and Spray with 0.5% hydrocortisone to provide relief from hot spots, wounds, and other infections.

Arden MooreDr. Patricia Thomblison is a graduate of Oklahoma State University where she earned her Doctor of Veterinary Medicine and Master of Science. She has devoted her career to keeping pets healthy and happy. She has served many roles in this endeavor to educate veterinary professionals and pet parents on many topics of animal health. She has worn several hats in the areas of clinical pathology, nutrition, and parasitology. She is a well-respected medical editor, veterinary consultant, and lecturer. She enjoys the company of her two cats, Miles Davis and Stewart, as well as a rambunctious dog named Barnibus and her children’s dogs.

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