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DrBarchas.com is free resource for people with pets. Searchable articles are available on diseases, behavior, symptoms, and medical treatments for dogs and cats. Photo galleries contain submitted pictures of pets and people.

About Eric Barchas, D.V.M.

Eric Barchas, DVM is a veterinarian who lives and works in the San Francisco Bay Area. His emphasis is on small animal medicine, emergency medicine, hospice and wellness. An avid traveler, he has studied lions in Botswana and salmon in southern Chile.

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The contents of this page are provided for general informational purposes only. Under no circumstances should this page be substituted for professional consultation with a veterinarian.

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Hair Loss, Shedding, Balding, and Unkempt Hair in Cats and Dogs

Shedding, unkempt hair, and hair loss in pets are extremely common complaints among owners.   In many cases, shedding is normal and harmless for the pet.  However, hair loss leading to baldness, or hair loss accompanied by itchy, red, scabby, moist, or malodorous skin usually is linked to a medical problem.

Common Causes

More common causes are listed first.  Less common causes are listed later.

  • Normal hair loss, or shedding, occurs in every cat and dog (except for those that have been bred to be hairless).  And, regardless of the amount of hair being shed by a pet, a medical problem is unlikely if there are no areas of thin hair, matted hair or balding on the animal.
  • Allergies to fleas, pollen, food, or environmental allergens may cause hair loss and baldness. Often, itching, scabbing, and redness of the skin occur concurrently.
  • Skin infections with bacteria or yeast cause hair loss.
  • Over-grooming may cause hair loss in both dogs and cats. In cats, a syndrome called psychogenic alopecia may cause hair loss, usually on the abdomen. In dogs, a syndrome called acral lick dermatitis may cause bald, inflamed areas to develop on the wrists or ankles.
  • Young dogs are prone to a syndrome called puppy mange. This syndrome is also known as demodectic mange, because it is caused by the Demodex mite.
  • Auto-immune disease, in which the immune system triggers skin irritations or skin lesions, can lead to hair loss. Minor, temporary problems with the immune system are especially common in puppies and kittens (this is similar to pimples in adolescent human beings).  Immune system-based hair loss in mature animals typically is chronic in nature.
  • Endocrine (glandular) disease, such as hypothyroidism or Cushing's disease in dogs, or hyperthyroidism in cats, may cause hair thinning.
  • Metabolic problems such as kidney disease or liver disease may cause hair to become unkempt or fall out.  Bladder infections may lead to unkempt hair.
  • Diabetic cats and dogs generally suffer from unkempt hair coats.
  • Dental disease may lead to poor grooming and unkempt hair.
  • Cancer may cause unkempt hair or baldness.
  • Foreign objects such as foxtails or splinters in the skin may lead to hair loss in the area near the object. In this case, it is common to find an open sore adjacent to the foreign object.
  • Ringworm can cause hair loss in pets.  Ringworm can spread to people.
  • Trauma to the skin, in the form of abrasions or lacerations, may cause hair loss.  As well, areas of scarred skin typically lack hair cover.
  • Mange, or scabies, is uncommon in developed areas of the world.   However, it can lead to hair loss with intense itching.  It also can spread to people.
  • Obesity (cats, dogs) and arthritis may interfere with proper grooming and lead to unkempt hair.
  • Rarely, adverse reactions to medications can cause hair loss.
  • A number of rare and exotic causes of hair loss exist.  These include flank alopecia of Dachshunds (similar to male pattern baldness in humans), seasonal hairloss, alopecia X, and many others.

Recommended Course of Action

If you note areas of baldness or thin hair on your pet, a veterinarian should evaluate the skin and perform a complete physical examination.

If you suspect that your pet is shedding excessively because you are finding large amounts of hair in the house, examine your pet carefully. Look for areas of thinning hair or baldness anywhere on the body, including the abdomen. If you note thin hair, bald areas, itching, or any area of skin that is thickened, red, irritated, moist, or bad smelling, a veterinarian should examine your pet.

If your pet seems comfortable and its skin and haircoat appear normal, it is probable that normal shedding is occurring.

As always, if you have any doubts about the situation, the safest course of action is to consult a veterinarian.

Copyright © Eric Barchas, DVM All rights reserved.
The contents of this page are provided for general informational purposes only. Under no circumstances should this page be substituted for professional consultation with a veterinarian.