There are many diseases and conditions which can cause a dog
to lose hair; some more common than others. This article will help reveal
some of the least common causes of hair loss in dogs and cats and some
of the most successful treatment options.
1. Chemotherapy -
Loss of hair due to chemotherapy.
Symptoms: Dogs with continuously growing hair (e.g. Poodles
and Maltese), often lose some hair; some may also lose whiskers.
Treatment: Hair will regrow after chemotherapy is discontinued;
be aware hair may regrow in a different color or texture.
2. Cyclic (cicatrical) Alopecia -
Growth cycle of hair stops at certain times of the year.
Symptoms: Symmetrical hair loss with definite borders; usually
on back and flanks; skin may become darker.
3. Diabetes Mellitus - Abnormal immunity makes
diabetic dogs susceptible to infection and other skin conditions.
Symptoms: Thin skin; some hair loss; seborrhea; recurrent
bacterial infections; unregulated dogs also have many other signs of
disease; may develop epidermal metabolic necrosis or xanthoma.
Treatment: Dietary changes; insulin.
4. Erythema Multiforme -
Hypersensitivity reaction to infections or drugs; may also be caused by
cancer or other diseases.
Symptoms: Hair loss, 'bull's-eye' lesions, and vesicles often
around mouth, ears, groin, and axilla; in some instances, ulcers develop;
Treatment: Treat or remove underlying cause.
5. Estrogen Responsive Dermatosis (ovarian
imbalance type II) - More common in young spayed dogs, and in Dachshunds and
Symptoms: Hair loss starting at the genital area and flanks
and moving forward; hair color may fade; coat is similar to a 'puppy coat'.
Treatment: Estrogen replacement therapy; caution - can
have severe side effects.
6. Flea Allergy Dermatitis - Severe reaction
by the animal to the saliva of the flea.
Symptoms: Intense itching, redness, hair loss papules, crusts,
and scales; sometimes development of infection or hot spots.
Treatment: Flea control in the environment and on the
dog; steroids and antihistamines to help control the itching.
7. Growth Hormone Responsive Alopecia - Not
well understood; thought to be caused by an enzyme deficiency or decrease
of adrenal hormones, which allows certain other hormones to accumulate
in the body. (more common in Pomeranians, Chow Chows, Keeshonden, Samoyeds,
Symptoms: Hair loss on neck, tail, and the back of the thighs;
skin darkens; usually starts when dog is less than two years old.
Treatment: Neuter animal; growth hormone; hormonal supplementation.
8. Hyperestrogenism (ovarian imbalance
type I) -
Rare disease in which female animals have excess levels
of estrogen; can be caused by cancer of the ovaries.
Symptoms: Symmetrical loss of hair; hair pulls out easily;
darkening of the skin; enlarged nipples and vulva; may rarely see seborrhea
Treatment: Spay; look for metastasis to the lungs.
9. Leishmaniasis - Caused by a parasite of
blood cells; can be transmitted to people who develop a very severe disease.
Symptoms: Hair loss, scaling, ulcers on nose and ears,
sometimes nodules; many other nonskin-related signs.
Treatment: Because it causes severe disease in people,
and treatment of dogs is not curative, euthanasia may be necessary.
10. Lice - Infection with several species of
Symptoms: Variable; itching, hair loss, crusts, rough hair
Treatment: Pyrethrin, ivermectin, Permethrin
(Do NOT use permethrin on cats).
11. Pattern Alopecia - Three types; hair loss
may occur on the ears of Dachshunds (pinnal
alopecia); neck, thighs, and tail of American Water Spaniels
and Portuguese Water Dogs; abdomen and the back of the thighs
of Dachshunds, Chihuahuas, Whippets, and Greyhounds.
Symptoms: Hair loss in areas described above.
12. Pelodera Dermatitis
- Accidental infection
with larvae from a
non-parasitic worm that lives in straw and other organic
Symptoms: Affects areas of skin touching ground; intense
itching, redness, hair loss, papules, crusts, and scales.
Treatment: Remove bedding; mild antibacterial shampoo;
steroids if necessary to control itching.
13. Pituitary dwarfism - Hereditary condition
in which the pituitary gland does not produce the necessary hormones.
Symptoms: Young puppies fail to grow; dogs retain puppy
coat and condition progresses to hair loss over much of the body; thin
skin, scales, and secondary infections.
Treatment: Hormone replacement therapy.
13. Sertoli Cell Tumor - Tumor of the testicles
in middle-aged dogs.
Symptoms: Male dogs take on female sexual characteristics;
hair loss, increased skin pigment, and reddened area on prepuce.
13. Testosterone Responsive Dermatosis - More
common in old
neutered dogs, and in Afghans.
Symptoms: Dull, scaly, dry coat; seborrhea; hair loss
in genital and anal areas progressing onto trunk.
Treatment: Testosterone replacement therapy.
13. Vitamin A Responsive Dermatosis - May not
be due to an actual deficiency of Vitamin A, but does respond to increased levels
in the diet (more common in Cocker Spaniels).
Symptoms: Seborrhea; odor; hair pulls out easily; pads
of feet thickened; thick scales on chest and abdomen, especially around
Treatment: Lifetime treatment with Vitamin A.
These articles on hair loss were provided to help you better
understand some of the causes, both common and rare, that may affect your pet.
As with any condition that affects your pet, it is always best
to consult with your veterinarian if you have any concerns or questions.
These articles are not provided as a substitute for diagnosing
any of these conditions.