Baldness and Hormone-Related Skin Disorders in Cats

Hormone Responsive Dermatosis and Alopecia in Cats

Two skin and hair disorders related to an imbalance of reproductive hormones are alopecia and dermatosis. 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 tests to positively identify the conditions, and the cause behind the skin and hair reactions, but there are a lot of reasons for why a cat would have these types of reactions. If all other indications point to an imbalance in hormones related to reproductive functioning, your veterinarian will try supplemental therapy to either increase or decrease hormone levels to a normal amount. Identification of alopecia and/or dermatosis is assured when the conditions spontaneously resolve after your cat has been given reproductive hormone therapy.

Symptoms and Types

Symptoms:

• Soft, or dry brittle fur
• Secondary dandruff
• Itching
• Darkening of the skin
• Blackheads on the skin
• Abnormal 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

Causes

Affected cats 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
• Occurs after spaying in non-cycling, intact females
• Occasionally seen during false pregnancy

Too much estrogen - ovarian imbalance I in females - rare

• Occurs due to cystic ovaries, ovarian tumors (rare), or from estrogen overdose (from medicine administered to the cat by a caregiver)

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

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

Testosterone-responsive - old castrated males - rare

• Low androgen levels suspected

Castration-responsive - intact males with normal, descended testicles

• Onset is at one to four years or older

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

Diagnosis

You will need to give a thorough history of your cat'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 cat, including a biochemical profile, a complete blood count, a urinalysis, and an electrolyte panel. Serum sex hormone tests will often show as normal in these cats. A skin biopsy (tissue sample) 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. 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.