Is your pet shedding too much for comfort? If you’ve noticed that your dog or cat has thinning hair, or has several bald spots, your pet may have alopecia.


According to, hair loss (alopecia) is a fairly common disorder in dogs and cats that causes partial or complete hair loss. This may appear as areas completely without hair or areas with thinning hair. You may also notice some swelling, redness, crusting or inflammation around the affected areas.

While alopecia may affect dogs and cats of all breeds, life stages, and gender, there are several reasons why your pet is losing their hair.


Skin parasites and infections

The most common cause for hair loss in dogs and cats are pet parasites like fleas, lice, mites, and ticks. These skin parasites cause the animal to itch and bite at the infected area, consequently their hair is chewed on or broken off. When your pet continuously bites at their fur, this may lead to other skin infections like yeast, ringworm, and bacteria that also cause more itching and biting.

Pay attention to where the hair loss occurs. This usually signifies what kind of parasite is the culprit. Fleas usually attack the back over hips, and lice focuses on the back and back legs, while mites that cause mange target the eyes, ears, mouth, and elbows.

Hair loss due to an allergic reaction to fleas and other pet parasites are easily treated with topical flea treatments and removing the fleas from the environment. Make sure to bathe your pets with an all-natural anti-flea and tick shampoo, and treat your home with an all-natural anti-flea and tick spray to get rid of any infestations in your pet’s surroundings.

For bacterial or fungal infections and mange, this is commonly treated with medicated shampoos and antibiotics only if needed.


Behavior (excessive grooming and anxiety)

Hair loss in pets may also be caused by behavioral problems. Excessive grooming and licking is usually caused by separation anxiety or boredom. Dogs tend to excessively lick their paws or legs when left alone for a long period of time. Cats may also over groom themselves when left with nothing to do.

To ease your pet’s boredom and separation anxiety, entertain them with fun toys that will help keep them busy while they wait for you to get home.



Pets with allergies usually have itchy skin that causes them to excessively scratch and chew their hair out.

The usual causes for allergies in pets are:

  • Food allergies – usually caused by grains (wheat, corn, soy), meats and fish (beef, lamb, pork, salmon), milk and yeast
  • Inhaled allergens like pollen, cigarette smoke, and perfumes
  • Contact allergies from harmful chemicals in their environment


Poor nutrition

Pets that are malnourished often have thin, dull coats. When your pet is not given enough nutrients, their hair becomes dull, loosens, and easily falls out. A balanced supply of nutrients helps their hair remain attached to their skin.

It’s best to supplement your pet with vitamins, minerals, antioxidants, and Omega 3 and Omega 6 fatty acids to support healthy skin and fur.


Abnormal organ function 

Specific organ functions also have a direct influence on hair loss. If hair loss is caused by malfunction of adrenals, liver, kidneys, ovaries, testicles, or thyroid, pets may also show these signs:

  • Behavior changes and irritability 
  • Lethargy
  • Restlessness
  • Weight gain or weight loss
  • Increased water consumption
  • Increased urination


Inadequate blood flow

When the blood doesn't circulate adequately, hair will not grow well. Pets with weak hearts, low blood pressure, and chronic anemia may have cool skin and dull coats. The thinning coat is from hair falling off directly from the follicle rather than being licked and broken off.


Excessive or deficient hormone levels

Hormones like testosterone, estrogen, melatonin, growth hormone, thyroxin, and cortisol have a direct influence on hair growth. Abnormal levels of these hormones may cause hair to fall off. Hypothyroidism or insufficient thyroxin, is usually seen in dogs, and causes thinning hair over the back. Hyperthyroidism or overproduction of thyroxin, is usually seen in cats that have poorly groomed and matted, oily coats.

When cortisol levels are too high (Cushing’s disease), or too low (Addison’s disease), hair loss may also occur and clipped hair may grow back very slowly.


Pet medications

Some oral, topical and injected steroid and flea medications may also contribute to hair loss in pets. Steroid medications may cause the hair to completely fall off from the follicles. For topical and injected medications, this may cause hair loss only at the specific area of application.


How To Diagnose and Treat Hair Loss

Hair loss in dogs and cats is caused by many different medical and behavioral problems. Specific treatments for hair loss in pets will depend on the underlying cause. It is best to consult with your veterinarian to properly identify the cause of the hair loss. Your veterinarian may need to make a thorough examination to be able to determine the appropriate medications and course of action.