Welcome

Shop All

Hair Loss Info

Hair Loss Blog Topics

	Dr. Michael Dym Holistic & Conventional Veterinarian
"Over 19 years of caring for the well-being of pets" Visit his Ask the Vet blog.

Causes of Hair Loss in Dogs and Cats

What Can Cause Pets to Lose Their Hair?

Hair loss in dogs and cats can appear as areas without hair (bald patches or alopecia) or areas with thinning hair. There may also be changes in the skin with increased pigmentation, redness, swelling, crusting, flaking, or moist oozing and discharge. There may be an unpleasant odor. If hair loss is caused by malfunction of adrenals, liver, kidneys, ovaries, testicles, or thyroid, pets may also have these signs:

Behavior changes and irritability

Lethargy

Restlessness

Weight gain or weight loss

Increased water consumption

Increased urination (polyuria/polydipsia or PU/PD)

When diagnosing hair loss, vets will look for pattern of hair loss, whether it is caused be chewing or shedding, and if the hair loss is related to an underlying illness

How Is the Cause of Hair Loss Diagnosed in Dogs and Cats?

Hair loss in dogs and hair loss in cats is caused by so many different medical and behavioral problems that taking a thorough history is essential to steer the diagnosis toward problems caused by illness, infection, stress, surgery, behavior, pregnancy, parasites, vaccinations, or drugs. In addition to a thorough history, some of the following medical tests can be necessary to reach a diagnosis: combing for flea dirt, skin scrapings, skin biopsy, skin culture, hair culture for fungal growth, blood test, urinalysis, X-ray, and Woods lamp illumination.

Evaluating Hair Loss in Dogs and Cats

Before ordering medical tests, veterinarians evaluate:

The pattern of hair loss
Whether the hairs fell out or were chewed out
Whether there are signs of systemic illness

Patterns of Hair Loss in Dogs and Hair Loss in Cats

Among the hair loss in dogs and cats, patterns may include:

Thin all over
Thin over the back and sides
Thin over the ears
Thin along the neck
Thin under the belly
Complete loss along sides and down tail leaving the tip with hair (like a lion's tassel)
Circular patches of baldness
Bald abdomen
Bald patches on fore legs above the wrist (carpus)
Bald patches on back legs on the side above the ankle (tarsus)
Balding along the back of the hind limbs up over the scrotum

Generally, the pattern of balding or thinning suggests the cause of hair loss. For example, pets with chewed off hair and bald, patchy areas over the base of the tail, inside the back legs, and on the abdomen often have fleas. Pets with thin skin and hair loss along the back and sides, and down the tail, but not the tip of the tail often have high cortisol levels and Cushing's disease. Pets with thick skin, weight gain and dull, thinning hair over the back and sides often have low thyroid levels and hypothyroid disease.

Hair Loss Due to Chewing and Shedding

To evaluate whether hair was chewed off or fell out, hair is put under the microscope. Hair that falls out has a root with a little bulb. Hair that is chewed out does not end in a smooth bulb. Hair that falls out suggests illness, hormonal, or endocrine problems, but hair that is chewed suggests fleas, other external parasites, or behavioral problems.

Signs of an Underlying Disease or Illness

Often pets that are ill hide symptoms and we first realize they might be ill because the hair falls out. For example, pets with Cushing's disease begin drinking more and urinating more, but we might not notice until we realize their hair is falling out on their sides. Pets with hypothyroid disease become lethargic and put on weight, but we might not realize this is a medical problem until their hair thins or fails to grow back in after they are clipped.

Medical Tests for Diagnosing the Cause of Hair Loss in Dogs and Cats

The following are tests done to diagnose the cause of hair loss:

Test	Used To Identify	What Test Confirms
Combing for flea dirt	Fleas	An especially important test for pets that groom themselves and remove fleas efficiently—especially cats. By finding flea dirt, we confirm that fleas are a problem for the pet.
Microscopic exam of skin scrapings	Demodex mites Lice Scabies Yeast	Some parasites living on the skin or in tunnels in the skin are extremely difficult to find. If the parasite is found, this is a positive test. If no parasites are found, it is possible they are still causing the problem but have eluded us. Yeast organisms are easily identified on skin scrapings and can explain why a pet is itchy if there are no lice, mites, or fleas.
Microscopic exam of ear discharge	Ear mites	In some cats thinning of hair around the ears on the face is due to mites
Culture of skin discharge	Bacteria	Culture and sensitivity tests find the cause and the best treatment for the infection so that money is not spent on ineffective medications.
Fungal culture of hair shafts	Ringworm (Dermatophytosis)	Some pets—usually cats—carry ringworm that doesn’t bother them but does infect other pets. Culturing all pets in the house helps identify pets that are obviously infected and those that are silent carriers of ringworm.
Skin biopsy	Pemphigus, Squamous cell carcinoma Basal cell carcinoma Mast cell tumors Melanoma Vaccine-induced Dermatopathy	Immune diseases, skin cancers, and vaccine-induced skin diseases are confirmed by biopsy specimens.
Blood tests	Diabetes Cushing’s disease Hypothyroidism Hyperthyroidism Sex hormone alopecia Lymphoma	Pets with endocrine diseases and those with cancer of the blood, such as lymphoma, are diagnosed with blood tests.
Urinalysis	Diabetes Cushing’s disease	Urinalysis helps diagnose the severity of diseases. For example, when diabetes is severe there will be sugar and ketones in the urine. Urinalysis helps diagnose Cushing’s disease by comparing the ratio of cortisol to creatinine.
Woods lamp illumination	Ringworm (Dermatophytes)	Some ringworm organisms fluoresce under a Woods lamp, but some do not. Pets with a negative test may still have ringworm infections.
X-ray	Cancer	Internal cancers that can cause rapid hair loss with hair that pulls out in clumps may be diagnosed with X-rays.
Weight	Cancer Diabetes Hyperthyroidism	Rapid weight loss indicates hair loss is caused by a serious organ disease.


	Hair Loss in Dogs and Cats Causes of Hair Loss in Dogs and Cats Hair Loss Treatment for Dogs and Cats

Help / Customer Service	My Account	PetMeds® Sites	PetMeds® Programs
Our 100% Guarantee About Us Contact Us FAQs PetMeds® Help Privacy Policy Printable Order Form Site Map Testimonials Vet Directory Request a Catalog Home	Login Email Preferences Reorder Easy refill Track my order My Account Page My pet has passed away	PetMeds� Blog PetHealth 101� Product Reviews Product Questions & Answers PetMeds� Charitable Causes 1-800-PetMeds� Careers PetMeds® Investor Relations pet meds Pet Meds Photos Pet Meds News Pet Health Articles	Affiliate Program Corporate Program Shelter & Rescue Program Join our Social Network PetMeds® on Facebook PetMeds® on Twitter PetMeds® on YouTube PetMeds® Google+ PetMeds® LinkedIn
Copyright � 2012 PetMed Express, Inc. All Rights Reserved.

VETERINARY-VERIFIED INTERNET PHARMACY PRACTICE SITES(CM) Online Veterinary Pharmacy Services

1800PetMeds.com has earned Veterinary-Verified Internet Pharmacy Practice Sites(CM) (Vet-VIPPS(CM)) accreditation through the National Association of Boards of Pharmacy® (NABP®).