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Hormone Responsive Dermatosis and Alopecia in Dogs

Alopecia and dermatosis are skin and hair disorders related to an imbalance of reproductive hormones. More specifically, alopecia is characterized by a loss of hair leading to baldness, and dermatosis is characterized by a diseased condition of the skin. There are a lot of reasons for why a dog would have these types of reactions, but if all indications point to an imbalance in hormones related to reproductive functioning, your veterinarian will try supplemental therapy to either lower or raise hormone levels to a normal amount. Identification of hormone related alopecia and/or dermatosis is assured when the conditions spontaneously resolve after the use of reproductive hormone therapy.

Symptoms and Types

Symptoms:

• Soft, or dry brittle fur
• Secondary dandruff
• Itching
• Darkening of the skin
• Blackheads on the skin
• Abnormal skin or shape of nipples, mammary glands, vulva, prepuce (foreskin of the penis or clitoris), testicles, ovaries and prostate gland
• Secondary bacterial infection
• Inflammation of the outer ear with wax build-up
• Wetting the floor

Types:

• Alopecia (Early stage hair loss)
  • Perineum (area between the vulva/scrotum and the anus)
  • Stomach
  • Thighs
  • Back of the neck

• Alopecia (Later stage hair loss)
  • Rump
  • Flank

• Dogs with testicular tumors will have
  • Enlargement of the tail gland
  • Enlargement of the perianal glands (around the anus)

Causes

Affected animals are categorized, and treated, according to the measurable amount of reproductive hormones being produced in the body:

Estrogen-responsive - ovarian imbalance II in females - rare

• Adrenal gland reproductive hormones are below normal levels
• Affects young adult dachshunds and boxers
• Occurs after spaying in non-cycling, intact females
• Occasionally seen during false pregnancy
• Variant - cyclical flank baldness and darkening of the skin in airedales, boxers, and English bulldogs

Too much estrogen - ovarian imbalance I in females - rare

• Occurs due to cystic ovaries (in English bulldogs especially), ovarian tumors (rare), or from estrogen overdose (from medicine administered to the animal by a caregiver)

Too much estrogen – in intact male dogs with testicular tumors

• Estrogen excess due to testicular tumors
• Failure of one or both testes to descend (cryptorchidism)
• Boxers, Shetland sheepdogs, Weimaraners, German shepherds, Cairn terriers, Pekingese, and Collies are predisposed
• Male pseudohermaphrodite (internal reproductive organs of one gender with external reproductive organs of the other gender) - affecting Miniature schnauzers

Too much androgen (male reproductive hormone) - associated with testicular tumors in intact, non-neutered males

• Androgen-producing testicular tumors
• Idiopathic (unknown) male feminizing syndrome (male animal takes on female behavior)

Testosterone-responsive – in older, castrated males - rare

• Afghan hounds are predisposed
• Low androgen levels suspected

Castration-responsive - intact males with normal, descended testicles

• Onset is at one to four years or older
• Chow chows, Samoyeds, Keeshonden, Pomeranians, Siberian huskies, Alaskan malamutes, and Miniature poodles are predisposed

Adrenal reproductive hormone imbalance - adrenal hyperplasia–like syndrome (enlargement of tissue)

• Adrenal enzyme (21-hydroxylase) deficiency resulting in excessive adrenal androgen (male reproductive hormone), or progesterone secretion (female reproductive hormone)
• Affects males and females, intact or neutered
• Onset is one to five years of age
• Pomeranians

Diagnosis

You will need to give a thorough history of your dog's health, including a background history of symptoms, and possible incidents that might have preceded this condition. Your veterinarian will then perform a thorough physical exam on your dog, including a biochemical profile, a complete blood count, a urinalysis, and an electrolyte panel. Serum sex hormone tests will often return as normal in affected dogs. A skin biopsy can illustrate abnormal sex hormone receptors in the skin.

X-ray, ultrasonography, and laparoscopy (using a small camera to examine the interior of the abdomen) imaging can be used for detection of ovarian abnormalities, testicular disorders and cancer.

An adrenocorticotropin hormone (ACTH) stimulation test, and an adrenal reproductive hormone test may be performed to measure the functional capability of the adrenal gland, and to be sure that it is specifically producing reproductive hormones. And a Gonadotropin-releasing hormone (GnRH) response test can demonstrate the response of the cells in the testes and ovaries to gonadotropin hormones. Specifically, the hormones that produce testosterone, primarily.